by Oleg Artamonov
11/07/2007 | 11:31 AM
Topower is a popular manufacturer. Besides making a wide range of PSUs for such brands as Tagan, BeQuiet, Mushkin and OCZ, the company is promoting its own brand, offering boxed PSUs of varying wattage and functionality.
<%BANNER[article]%>Topower’s product line consists of a few series, or generations, of power supplies called P5, P6, P7, etc. The series number is indicated in the PSU’s model name. For example, the TOP-1000P9 U14 model belongs to the newest P9 series (the bigger the number, the newer the series is). Besides that, there is a small number of "proper-name" models (for example, Silent Green) for which the series number is not indicated explicitly.
This review is mostly concerned with products from the P7 and P8 series. Additionally, it includes one Silent Green model and one Tagan PSU which is manufactured by Topower. To remind you, we have already tested the newest P9 series model called TOP-1000P9 U14 in an earlier article called 1000W Power Supply Unit Roundup. The same article covers the Tagan TG1100-U96 PSU which is developed and manufactured by Topower.
Don’t be surprised at finding a Tagan product in this review. There’s nothing wrong in this. Topower is the OEM supplier of PSUs for Tagan, so I thought it would be logical to test it now.
The packaging of the PSU deserves a special word. It comes in a leather-sheathed wooden box with two drawers. Tagan is prone to such original solutions I should acknowledge. Some of its other products are shipped in a leather trunk, for example.
The top drawer contains cables, which are detachable. The PSU itself is in the bottom drawer.
The PSU is cooled with one 135mm fan (interestingly, such models are suffixed “U14” rather than “U35” in Tower’s nomenclature) and is about the same size as the standard ATX power supply. It is only 15mm longer to accommodate the larger fan. The case is painted a matte black.
The rear panel offers connectors for detachable cables: two for graphics cards and six for various peripherals. The connectors differ not only in color but also in the position of the key, making it impossible to connect anything wrong.
The PSU employs two power transformers. That’s an unusual solution for a 500W unit since this wattage isn’t high by today’s standards. I guess it is the consequence of unification of parts (particularly, printed circuit boards) for different PSU models. Tagan must be using the same PCB for PSUs of higher wattages for which two transformers are more appropriate.
Besides that, the TG500-U35 features independent regulation of the output voltages and active PFC. In other words, it’s got everything a modern PSU is expected to have.
The card with the output connectors is located near the back panel of the PSU.
The combined load capacity of the +12V rail is 432W. It is divided into four output lines with a limit of 20A on each.
I call such outputs “virtual” because there is actually only one +12V power rail inside the PSU but it has four shunts to control the load current on the output, each of which makes up one “virtual” +12V output line. The shunts can be easily seen in the photo above: they are the short thick U-shaped things among the wires soldered into the PCB.
The PSU offers the following cables and connectors:
The following is supplied together with the PSU:
Three drawbacks can be noted here. First, the detachable cables have handy but very large connectors. There must be some 6-7 centimeters of free space behind the PSU in your system case for you to be able to plug these cables in normally.
Second, the power connectors for graphics cards (both 6- and 4-pin ones) have clumsy rubber knobs which even make it impossible to connect this cable into some graphics cards as the knob presses against the card’s PCB. In this case you have to take a sharp knife and carefully remove this embellishment from the cable.
And third, these graphics card cables are screened and packed into thick plastic tubes. There is no practical sense in screening power wires while the thick plastic makes them stiff and unwilling to be laid properly inside the system case.
Together with an APC SmartUPS SC 620 this power supply worked well at loads below 350W. This refutes the myth you can learn at many Web forums that all PSUs with active PFC have problems with uninterruptible power supplies. In actual fact, only some older PSU models, the TG500-U35 cannot be counted among, have such problems.
The PSU features superb stability of the output voltages. None of the three tracked voltages leaves the allowable limits at any permissible balance of loads.
At a load of 480W the output ripple amounts to 43 millivolts on the +5V rail (the allowable maximum being 50 millivolts), 65 milliseconds on the +12V rail (the allowable maximum being 120 millivolts), and 18 millivolts on the +3.3V rail (the allowable maximum being 50 millivolts). It means the PSU meets the output voltage ripple requirements.
The PSU is cooled with a 135mm Globe Fan RL4T S1352512MB that has a translucent impeller but lacks any highlighting.
The fan is attached to the PSU case via shock-absorbing rubber spacers to minimize noise. I should note, however, that it is the air flow and the buzz of the bearing and impeller that create most noise you hear from a fan. The transfer of vibration to the PSU case doesn’t add much noise to that.
As you could see above, the PSU sticker shows a diagram of correlation between the fan speed and the output power but it has nothing to do with reality. The fan starts out at a speed of 970rpm and accelerates to 1731rpm as the load grows. The PSU is average in terms of noisiness. It might be called quiet if its fan worked at a constant speed at loads below 250-300W.
The PSU is 80% efficient, which is a rather average result as today’s PSUs go. The power factor is above 0.95.
The Tagan TG500-U35 is a good product. It is free from serious drawbacks, delivers stable voltages, offers a sufficient selection of connectors, and is not very noisy. This PSU can be a good choice for people who need a quality and high-wattage power source. My only gripe is about the screened cables and rubber connectors. I think that power connectors and cables should be handy rather than pretty, but it’s just the opposite in this PSU.
The first PSU in this review that is selling under Topower’s own brand is a model with a 12cm fan. A little while ago I would regard an 8cm fan as a classic solution but now 12cm models can be called such because the newest PSUs are often equipped with 14cm fans.
The case has a dark glossy – and easily scratchable – coating. It is noticeably longer than the typical ATX power supply, which is rather unusual for a model with a rather low wattage rating because there should be no problem to assemble one in a case with the standard 145cm length.
Indeed, there is quite a lot of free room on both sides of the PCB. The reason is not quite clear. Installing 80mm fans (for PSUs with such a cooling solution) or power connectors (for PSUs with detachable cables) would require a different case anyway, so the manufacturer can save but little on product unification, and this doesn’t agree with the retail pricing of Topower PSUs.
The PSU features the long-classic circuit design with a half-bridge transformer. This time-tested design is not very efficient, though. The output voltages are regulated independently as is indicated by the three chokes in the left part of the photograph (there would be only two in a PSU with joint regulation).
The PSU has neither passive nor active power factor correction. It doesn’t have a mains voltage switch and can only work in 200V power grids. The quality of manufacture is high, I have no complaints about it.
The label shows specifications for four models that vary in wattage but are based on the same platform. The name of the given model is printed on a sticker above the main label.
The TOP-500P7 U12 is an ATX12V 2.0 power supply that allows a current of 33A (396W) on the +12V rail but doesn’t split this rail into multiple output lines. As I have repeatedly noted in my reviews, this kind of splitting is only introduced to comply with the EN-60950 safety regulation and has no effect on the stability of the PSU.
The PSU is equipped with the following cables and connectors:
The graphics card cables are screened and sleeved into transparent plastic tubes (they are rather stiff as a consequence). The mainboard cable has a plaited tube on. The other cables are just twisted like a twisted pair.
Featuring dedicated voltage regulation, the PSU delivers very stable voltages just as you may have expected. None of the three tracked voltages gets close to the maximum allowable deflection of 5% from the nominal value at any load.
There are problems with the output voltage ripple, though. At maximum load the +5V oscillogram shows spikes that are somewhat higher than the 50 millivolts permitted by the standard. The manufacturer should have used better electrolytic capacitors on the output or shunt them with additional ceramic capacitors.
There is low-frequency pulsation, too. It is quite strong on the +12V rail although never goes beyond the allowable maximum of 120 millivolts.
The PSU is cooled with a 120x120x25mm fan (Globe Fan S1202512M).
The fan speed is constant at loads below 350W. After that it grows up linearly, but not too fast. If the initial speed were lower, the TOP-500P7 U12 might be called a quiet PSU. At 1100rpm it is only average in terms of noisiness. The temperature increase inside the PSU is quite high, by the way.
I guess there are two reasons for the temperature to increase so much despite the not-very-slow fan: a rather low efficiency and a high component density of the PCB (contrary to the common opinion, heatsinks with a lot of narrow ribs are not very efficient because they provide a high resistance to air flow; you can note that the quiet PSUs from Seasonic, Corsair and Zalman have heatsinks of a simpler shape than the ones employed in the TOP-500P7).
The efficiency is constant through a large range of loads but is only 76% at the maximum. That’s a very modest result for a modern PSU. The power factor is not high due to the lack of any type of correction.
So, the TOP-500P7 U12 is a regular mainstream PSU. None of its parameters is exceptional, and its circuit design is somewhat outdated. The PSU even didn’t meet the requirements of ATX12V Power Supply Design Guide in terms of output voltage ripple, even though by just a little. The increased length of the case is a drawback, too. The PSU of this wattage might have been designed within a standard-size case.
For the previous PSU the U12 suffix denoted a 12cm cooling fan. Here, it is changed into FR and the cooling system is different. I will discuss the two FR products both together as they are based on the same platform and do not differ in anything save for the max output power (and the ratings of some components).
The PSUs are cooled with two 80mm fans. One fan is pumping air into the PSU case and the other is exhausting it. This design helps increase the amount of transferred air as two fans create a high static pressure. It also helps avoid “dead zones” inside the PSU in which the air flow would be weak with only one fan.
Most of the interior is occupied by large black ribbed heatsinks. There is no free space on the sides of the PCB – the fans are in there. This explains the increased length of the case in comparison with the typical ATX power supply.
But taking a look from a side, you can easily see that this model is identical to the TOP-500P7 U12 in its circuit design. They are based on the same PCB.
The models with a wattage of 650W and higher have a switch that determines if the +12V rail is divided into multiple output lines with a current limit of 18-20A on each (the Split position) or not (the Combined position). This proves my point that the “virtual” +12V lines do not require the PSU to have some special design and do not increase its stability. You can flip the switch into this or that position and make sure the output voltages are not affected by that at all.
The junior, 600W, model (TOP-600P7 FR) doesn’t have that switch. It has one +12V line with an allowable current of 40A (in the TOP-700P7 FR the allowable current is 564W/12V = 47A in the Combined mode).
The PSUs have the following cables and connectors:
The graphics card cables are screened and sleeved into transparent plastic tubes (rather stiff tubes, I should confess). The mainboard cable has a plaited tube on. The other cables are just twisted like a twisted pair as you can see in the photo of a Molex connector above.
When working with an APC SmartUPS SC 620 both PSUs had a max allowable load of 295W. They both switched to the batteries successfully.
The cross-load diagram of the 600W model looks like the one of the TOP-500P7 U12 (see above): the +12V and +5V voltages boast excellent stability, and the +3.3V voltage is just good.
The 700W model proves even better in this test: its +3.3V voltage almost never leaves the green zone. You can only find a few yellow spots in the diagram.
Alas, the rest of the tests didn’t go well for the PSUs. The 700W model would overheat at full load. It would produce a characteristic noxious smell, although sustained such load continuously without failure.
The output voltage ripple of the 600W model is close to the allowable limit at full load. The 700W model violates the limits: it has a pulsation with an amplitude of 65 millivolts on the +5V rail, the allowable maximum being 50 millivolts.
There was also low-frequency (100Hz) pulsation. It amounted to 50 millivolts on the +12V rail at full load. That’s quite a lot, although below the allowable maximum of 120 millivolts. Anyway, I think that a well-designed PSU should have no low-frequency pulsation of the output voltages at all.
Both PSUs employ Globe Fan S0802512HD fans of the standard form-factor of 80x80x25mm.
The fans are fastened to the PSU case through rubber pads to minimize vibrations. Talking about that, I should note that the vibration of the fan frame is not the only and even not the main source of noise unless you’ve got a defective fan. It is the noise of the air flow, the bearings and the impeller that is the most annoying usually.
The regulation of the fan speed is implemented identically in both PSUs, so I’ll discuss the senior model. This diagram applies to the TOP-600P7 FR as well, with an appropriate limitation in output power.
So, the fans start out at a speed of 1800-1900rpm and maintain this speed until a load of 400W. After that they accelerate quickly. As a result, the PSU is not quiet. Its two fans and high component density (the latter means a high aerodynamic resistance inside the PSU and an increased noise of the air flow that’s passing through it) contribute to this.
The PSU is not cool, either. As I wrote above, the 700W model would produce an annoying smell when under full load. You can see the reason now: the temperature of the air that’s passing through the PSU increases by 21°C. I guess the high component density is the problem again. The fans just cannot pump enough of air through the PSU. This is indicated by the fact that the temperature growth is not affected by the acceleration of the fans at loads over 400W.
Both PSUs are 74-75% efficient. This is not high by today’s standards, which may be another cause for the overheat. The power factor barely reached 0.7 because these PSUs have neither active nor passive power factor correction.
Like the above-discussed TOP-500P7 U12, these two PSUs - TOP-600P7 FR and TOP-700P7 FR – are mainstream, even bottom-mainstream, products. They are not quiet and are prone to overheat at high loads. Their dimensions are larger than the standard, the efficiency is low, and the output voltage ripple violates the limits prescribed by the standard. The superb stability of the output voltages is in fact the only good point of these products.
The U12 and FR series differ in the cooling system only. The former uses 120mm fans, and the latter uses 80mm fans in couples.
As opposed to most other Topower PSUs, this one has a proper name. It is called Silent Green.
The PSU is indeed painted this rather unusual color. The case, the label, the nylon sleeves on the cables and even the rubber knobs on the connectors are all various shades of green, from yellow-green to blue-green.
The highlighting is green, too. Well, the designers couldn’t quite resist the temptation to employ currently fashionable blue LEDs. The “Combined” LED (I’ll explain its function shortly) is just that color. I don’t quite understand why it couldn’t be made green like the rest of the PSU.
The Silent Green is different internally from the P7 series products I’ve discussed above. It doesn’t have independent regulation of voltages, but instead it has acquired active PFC.
Comparing it with modern high-wattage expensive PSUs, this one has got a traditional circuit design with a CM6800G-based controller and a single-ended inverter.
The Silent Green has two non-detachable cables – those of the CPU and mainboard. The others are to be connected as necessary to the 6-pin connectors you can find on its back panel.
The PSU is equipped with the following cables and connectors:
Included with the PSU are:
There are two things I want to complain about. First, there is only one cable with SATA power connectors. If you’ve got a HDD and a DVD drive with SATA interfaces, it would be convenient to use two power cables for them. Second, the cables are awfully impractical. They have thick plastic tubes on (the tubes shine in ultraviolet light and look pretty, but they are just too unwilling to bend) and the connectors have rubber heads. The latter was obviously done to maintain the common color scheme (otherwise, the connectors would be just black), but it becomes a problem when you are trying to plug those connectors in. This may be even impossible if there is not enough space around the connection spot.
The Silent Green complies with the ATX12V 2.0 requirements as concerns the allowable load on the +12V rail – up to 40A. It also has a high load capacity of the +5V rail, though.
Two +12V lines are indicated on the label, but it is actually a single power rail inside the PSU. It is single in every sense of the word because the protection gets disabled if the current exceeds the indicated 20A on either of the +12V lines. Topower calls this an “automatic combining of the lines” but it turns out that the lines were never separate. It is only due to marketing reasons that the label shows two 20A lines instead of a single 40A line. To make this more impressive, the blue LED marked as “Combined” lights up when there is a load of over 20A on any of the lines.
When working together with an APC SmartUPS SC 620, the maximum load power of the PSU was 365W if powered by the mains and 250W if powered by the batteries. This low allowable load (if it is exceeded, the UPS lights up its overload indicator when switching to the batteries or even shuts down altogether) means that the Silent Green may have troubles with UPSes. There is an opinion that all PSUs with active PFC have problems with UPSes, but that’s not true. Most modern PSUs are compatible with any UPS.
The cross-load diagram is not as pretty as the one of the previous models due to the lack of dedicated voltage regulation. Anyway, the result is quite acceptable. The voltages are within allowable limits in a broad range of loads. If installed into a modern high-performance PC, the Silent Green’s +5V voltage is going to be slightly too high and +12V voltage, normal or 1-2% lower than the nominal value.
It’s all right about the output voltage ripple: you can hardly see any pulsation in the oscillogram even at full load. It is much weaker than the allowable maximums.
The PSU doesn’t have low-frequency pulsation on its output.
The PSU is cooled with a 120x120x25mm fan (Globe Fan RL4G S1202512M).
The fan speed is constant at 1100rpm until a load of 200W with something. At max load it is higher than 2200rpm. So, this PSU is average in terms of noisiness. Most users are going to find it acceptable, but it is not exactly quiet. It is inferior to the models from Seasonic and Zalman we have tested in our labs in this respect.
The PSU has 83% efficiency and a power factor of higher than 95%. Both results are far from breaking any records, yet they are good even as today’s PSUs go. Here, the Silent Green differs dramatically from the P7 series that has a hopelessly outdated circuit design.
Although not without shortcomings such as poor compatibility with UPSes, not high stability of the output voltages and very impractical cables, the Silent Green TOP-600SG is overall superior to the TOP-600P7. It is quieter, provides a higher efficiency, and has a very low output voltage ripple (as opposed to the P7 series models that even didn’t meet the requirements of the industry standard to this parameter). It also features active PFC that supports an input voltage range of 90-264V without switches.
Now I return to the P7 series. This time these are high-wattage models with detachable cables. Perhaps they’ll prove to be better than the rather unsuccessful 500W and 600W models from the same series?
The CPU and mainboard cables are not detachable in the SEZ model and detachable in the FEZ model. I don’t quite grasp the idea, though. Did you ever see a PC without a mainboard?
The manufacturer doesn’t think it necessary to specify what exactly PSU is in the box. The picture on the package shows both the models (the FEZ on the left and the SEZ on the right) while the sticker only indicates the wattage of the PSU.
A lot of space is given to an illustrated description of technologies such as active PFC, quiet operation with automatic fan speed regulation, and a special relay that allows connecting other consumers to the PSU so that they would be shut down together with the PC.
Alas, the other side of the box looks like a practical joke. It turns out Topower has got a lot of “exclusive” technologies but our sample of the PSU has none of them. It doesn’t have active PFC or an additional relay or anything. These are just shown in the pictures for you to know such technologies exist. Theoretically. In other PSUs.
The two PSUs are identical in front view and look alike to the P7 FR models: a mains connector, an On/Off switch, and an 80mm fan. There is no input voltage switch – the PSUs can only work with 220VAC sources (I wonder if the company produces another model for the USA that works only at 110VAC or employs a switch).
Topower TOP-750P7 FEZ
The FEZ model has 11 connectors for detachable cables on the rear panel: for the mainboard, CPU, graphics cards and peripherals. Despite the color coding, you can see that nothing prevents you from plugging a HDD power cable into the 4-pin CPU connector as both have the same shape and size and the position of the keys. So, be careful when installing this PSU into your system.
Topower TOP-700P7 SEZ
The SEZ model has 8 connectors like the above-discussed Silent Green. The top two connectors are marked with a different color and meant for graphics cards. The bottom six connectors are for peripherals and do not differ in size, shape, and the position of the keys.
Topower TOP-700P7 SEZ
The TOP-700P7 SEZ is almost the same as the TOP-700P7 FR on the inside. It’s got the same PCB and circuit design, and is cooled with two “push-pull” fans, too. The only difference is the card with the output connectors.
Topower TOP-750P7 FEZ
The TOP-750P7 FEZ is almost like the SEZ model except for the design of the card with the output connectors.
The PSUs represent a classic topology. The half-bridge push-pull converter has been used for decades already. This design is simple and cheap, but cannot provide a high efficiency. That’s why most manufacturers have transitioned to various kinds of single-ended converters with high operating frequencies.
All the cables included with the PSU are screened and have a plastic casing. This screening has no practical meaning in terms of the effect on the PSU’s EMI and output voltage ripple, but it does make the cables stiff and unyielding. The photo above shows that the cables hardly fit into their own box while cables of other PSUs are usually just tied into a bunch with a couple of elastic bands.
The TOP-700P7 SEZ has the following cables and connectors:
The first three cables are detachable and 50cm long in the TOP-750P7 FEZ.
Included with the PSUs are the following cables:
The connectors are all equipped with rubber heads that may become a nuisance when you are plugging a cable in. You may even have to find a sharp knife and scrape those heads off the cables.
Interestingly, the PSUs have the same labels as the FR models except for a small sticker above that tells you the full name of the PSU. So, both PSUs comply with the ATX12V 2.0 standard and have multiple +12V output lines. As opposed to the FR models, they don’t have a Split/Combined switch.
The 700W unit boasts an excellent quality of regulation. None of the three tracked voltages deflects by more than 2% from the nominal value.
The output voltages of the senior model are somewhat less stable due to unclear reasons (the two PSUs have an identical circuit design). Anyway, none of the voltages violates the allowable limits at any permissible load on the PSU.
TOP-700P7 SEZ
TOP-750P7 FEZ
The oscillograms of the output voltage ripple show a familiar picture. Both PSUs are close to the allowable maximum of 50 millivolts (1 division of the vertical axis) on the +5V rail and even exceed it during individual spikes.
The PSUs are cooled with couples of Sanyo Denki "San Cooler 80" fans (9A0812H401 model, 80x80x25mm form-factor).
Their speed is constant (about 1500rpm) at loads below 200W. Then it grows up linearly to reach a maximum of 2700rpm. Despite the smaller fan speed in comparison with the above-discussed TOP-700P7 FR, the temperature of air was lower at the output. That’s an interesting thing, probably resulting from the use of different fans. Neither the TOP-750P7 FEZ nor the TOP-700P7 SEZ had overheat-related problems.
Alas, these PSUs have an efficiency of only 77%. The power factor is 0.7 (the PSUs don’t have any kind of power factor correction notwithstanding the pretty pictures on the boxes).
So, the SEZ and FEZ models of the P7 series are versions of the FR models with detachable cables. Alas, this is the single good point of their design. The cables themselves are impractical. It is going to be difficult to lay them properly in a small and even medium system case. Moreover, with their high stiffness they are going to mechanically stress the connector of the powered device (I can remember IBM’s ICL35 series HDDs in which a permanent stress on the power connector would often lead to a loss of contact between the hermetic block and the electronics card, and the HDD would just fail as the consequence). Very high stability of the output voltages is the only notable thing about the electrical parameters of these PSUs.
Now we have approached the newer P8 series of Topower products. Models within this series are distinguished not only with their wattage ratings but also with the output cable design. The U14 version is a PSU with non-detachable cables; there exist versions with detachable ones.
Traditionally for Topower, the box tells you the wattage, but not the particular model of the PSU contained within. The photograph shows two models with quite different fan types.
The U12 index denoted a PSU with a 12cm fan, so U14 means a PSU with a 14cm fan. It is a 13.5cm fan, to be exact, but the manufacturers round this number up.
The exterior hasn’t changed much since the U12 series otherwise. The case is still longer than the standard 145mm but there is a lot of free room inside. The PCB doesn’t occupy all the interior of the case.
The PSU has non-detachable cables. Most of them are twisted, without an additional exterior casing. The mainboard and CPU cables are sleeved. The graphics card cables are screened and covered with thick, stiff plastic.
Well, the technically meaningless screening of the output cables is not even as impressive as the screening of the mains cable. It could please an audiophile, I guess, for whom a whole small industry makes such cables. But I have to tell you that the screened mains cable and the gold-plated pins of the plug affect the appearance but not the characteristics. Just imagine that there is some 100 meters of ordinary cable going from the nearest substation to your wall socket. And this cable is connected not with gold-plated but with ordinary pins of fuses, an electricity supply meter, and various clamps. So what can 1.8 meters of screened cable with gold-plated pins do? Nothing at all. But it looks pretty for sure.
Also included with the PSU is a set of nonexpendable fabric braces and a couple of single-use braces to fasten the cables in the system case.
The PSU has the following cables and connectors:
The PSU has four “virtual” +12V lines with a max combined load of 624W. Note the full range of supply voltages – this is the result of using active PFC.
Alas, the TOP-700P8 U14 wasn’t good under real conditions. At a load over 550W I felt the smell of overheat plastic from it. At a load of 680W and an ambient temperature of 24°C (which is much lower than a normal temperature inside a system case) it just failed after 4 minutes of operation. That’s why I don’t publish the oscillograms of the output voltage ripple – I just couldn’t make them.
The cross-load diagram shows that the PSU doesn’t have independent regulation of voltages. Moreover, even if you compare it with the above-discussed Silent Green (that has combined regulation of voltages as well), the TOP-700P8 U14 is obviously inferior. The +5V voltage goes all the way from the bottom (4.75V) to top (5.25V) limit in the diagram. As a result, the PSU can only yield a maximum of 160-170W out of the promised 220W combined on the +5V and +3.3V rails.
The reason for the failure of the PSU becomes clear when you take a look at the diagram that shows the correlation between the fan speed and the load. Starting at a modest 830rpm, the fan reaches 1350rpm under a load of 400W and that’s all. Its speed doesn’t grow up at higher loads while the temperature of the PSU continues to grow. So, it is clear that the reason for the overheat and death of the PSU was the inadequate operation of the fan speed controller.
The efficiency is in fact the single good impression about the TOP-700P8 U14. The transition to the new circuit design helped the P8 series surpass the 80% barrier at last. The PSU is 84% efficient at the maximum; its power factor is 0.98. These are much better results than those of the outdated P7 series models described above.
Anyway, this PSU didn’t impress me much. It has poor stability of the output voltages, large dimensions and a faulty fan controller that allowed the PSU to die prematurely.
Although this PSU belongs to the P8 series too, its internal design proved to be completely different from the TOP-700P8 U14 (see above). I want to apologize for the lack of photographs. Photos of the interior of these two PSUs were lost due to technical reasons while I was preparing this review.
Well, the difference can be spotted on the outside, too, even though it is a small one. The position of the On/Off switch and the shape of the vent holes are somewhat different here.
The PSU is longer than the standard ATX unit, unfortunately. This is not dictated by technical considerations. As you can see in the photos, the 14cm fan and the PCB fit in easily, leaving a lot of free space.
The PSU has the following cables and connectors:
The mainboard and CPU cables have plaited sleeves. The graphics card cables have Topower’s traditional thick plastic casings, and it’s not easy to lay the cables normally in the system case. On the other hand, you don’t notice this problem much after the P7 SEZ and P7 FEZ series models in which all the cables are not only covered with plastic but also have plastic knobs on the connectors.
The PSU can yield up to 720W via its +12V rail (which is split into four outputs) but the allowable load on the +5V and +3.3V rails is as high as 240W. That’s quite a lot for an ATX12V 2.0 power supply.
The PSU has an active PFC device but its operation is accompanied with one defect. There is a high level of noise the PSU sends back into the mains. The oscillogram above shows the mains voltage (in blue) and the voltage consumed by the PSU (in red). It’s clear that the latter is modulated at a high frequency, and there are also short spikes superimposed on that modulation. This must be the result of some defects in the operation of the active PFC device in the way it is implemented in the TOP-800P8. I didn’t observe this problem with other Topower PSUs.
In practice this problem may show up as interference the PSU will produce to other electronic equipment plugged into the neighboring wall sockets. Alas, that’s exactly what happened to our testbed with the ensuing consequences to the accuracy of my measurements.
The individual dots that contrast with the overall picture are the result of interference the tested PSU produced to the relatively sensitive part of the testbed. I want to note that I didn’t have that problem with other PSUs.
Apart from that, it is easy to see that the TOP-800P8 U14 features independent regulation of voltages. It easily works under any allowable load, the output voltages never going out of the limits prescribed by the standard.
The output voltage ripple under full load is within acceptable limits. This is only high-frequency pulsation.
The PSU is cooled with a Globe Fan RL4B S1352512MB fan.
Its speed is constant at 980rpm under loads below 450W. After that it begins to grow up linearly, reaching a maximum of 1380rpm. The PSU has no overheat-related problems. The temperature of the air that’s passing through it grows but slightly, by less than 10°C. Moreover, the TOP-800P8 U14 is quiet at work. Perhaps it cannot match Seasonic’s S12 series PSUs in this respect, but most users are going to be satisfied surely.
The efficiency of this PSU lowers towards the maximum output power, reaching 85% at the maximum. The power factor isn’t high as power supplies with active PFC go. It is only higher than 0.9 at a load of 300W and more. That’s the result of the electromagnetic interference the PSU causes in the mains as I noted above.
Of course, the TOP-800P8 U14 surpasses P7 series products as well as the above-described TOP-700P8 in its characteristics. It is worthy of your interest as it yields stable voltages with low ripple and is also quiet at work. On the downside is the sloppy operation of the PFC device which results in the generation of EMI for other electronic equipment. There are also design issues: the case has an increased length, and the screening of the cables doesn’t provide any advantages while makes it more difficult to lay the cables out in the system case.
I should confess my impressions about Topower products are not all positive. The company seems to have a good potential and shows the ability to develop and manufacture interesting products, but too many of them have this or that defect. It’s just funny how those defects may show up – I can remind you of the clumsy rubber knobs on the connectors and of the stiff screened cables, for example.
Among the discussed products the Topower Silent Green TOP-600SG seems the most interesting. Although it is not exactly quiet, its parameters are going to satisfy most users. The Tagan TG500-U35 combines good parameters with an original, fascinating packaging.
The other models are not so interesting, unfortunately. The P7 series is obviously outdated now, and the PSUs from it didn’t meet the output voltage ripple requirements in my tests. The P8 series seems exciting on paper, but turns to be not so pretty in reality. The 700W PSU couldn’t work under full load while the 800W model would be good if it were not for the strange operation of its PFC (but I should acknowledge that the other parameters of this PSU meet all the requirements).