Summer has finally set in. And the warm weather brought a very troubling problem ofappropriate PC cooling. Practically all the devices - the graphics card, the CPU, theharddisk - heat while working and this heat should be dissipated the sooner the better.In this article we'll discuss the cooling of one of the most important parts of the PC -the processor.

All semiconductor devices, including the today's CPUs, emit energy in the form of heat,which should be dispersed, because the allowed heating range of any semiconductor lies atbest somewhere between -60C and 150C. If the temperature goes beyond the allowed boundaries,both may occur: the mechanical damage of the semiconductor structure and a drastic change ofthe electrical parameters. That's why since 486 processors, cooling has been given a specialplace and has been handled with great attention and concern. The CPUs were equipped with allkinds of cooling devices intended to prevent extreme overheating.

As for the new Intel Pentium III processors, which coolers we are going to consider in thisreview, here is the table of their temperature parameters:

	Intel Pentium III 450	Intel Pentium III 500	Intel Pentium III 550
Maximum heat emission, W	25.3	28	30.8
Maximum allowed core temperature, Co	90	90	80
Maximum allowed L2 cache temperature, Co	105	105	105
Maximum allowed plate temperature, Co	75	75	75

As we see, Intel Pentium III processors are supposed to dissipate more heat than theirpredecessors, Pentium II, but on the other hand, they heat more as well. Besides, you shouldalso bear in mind that Intel has now introduced a new parameter dealing with L2 cache temperature,which wasn't even mentioned for Intel Pentium II. So, it probably means that these chips turnedout also in need of cooling. However, their allowed temperature is somewhat higher than that ofthe core that's why it is not worth special consideration. Moreover, Intel strongly recommends tomaintain the temperature within the PC case at about 45C, so that to provide more efficient CPUcooling.

Intel also does its best to solve the problem of its own processors cooling. All the newprocessors are designed in a new cartridge - SECC2. This package differs from the so familiarSECC by a total lack of the front part, which has always served for the cooler fastening. As aresult of this peculiar design, the heatsink blown through by the fan touches directly themicrochip of the processor core and not the metallic cartridge surface. All these innovationsfirstly, allow a better heat dissipation, and secondly, provide easier access to L2 cache, whichnow also needs cooling. However, this is also not the last point that is worth noting here. Thecrystal coverage has been also changed. A new organic copper alloy - Organic Land Grid Array (OLGA),which can boast better heat conduction, is now used instead of the former Plastic Land Grid Array(PLGA). Thus, Intel proves once again that it cares about a more efficient cooling of its newprocessors.

Now let's take a look at this problem from a different point of view. The effective performanceof the processor cooler depends mainly on three things:

• The heatsink size. The larger is the heatsink surface, the more heat can it dissipate.However, a large heatsink is not enough for perfect cooling. And since the amount of thedissipated heat directly depends on the temperature difference at the heatsink surface, thefan also shouldn't be disregarded.
• The volume of the air blown through the heatsink. The heavier is the airflow going throughthe heatsink, the colder will it remain, and as a result it will provide a better cooling.
• The quality of the contact between the heatsink and the CPU (thermal interface). Of course,the material providing the contact between the heatsink and the processor core should possesshigh heat conduction. Besides, the contacting surfaces should be deprived of any roughness andthere shouldn't be any air cavities between them because air has very low heat conduction.

Well, we will run a small test to compare three coolers - a usual noname and two veryhigh-quality products from TennMax and Elan Vital.

Testing participants

Noname

Well, nothing special, actually. It is a usual cooler, which consists of a black heatsink withfew fins, and a fan of 50x50x10mm rotating at 4500rpm. The heatsink is made of aluminum, becausethis low-cost metal provides comparatively high heat conduction. There are also special coolingslips in the heatsink made opposite the cache chips. The fan equipped with a rotation sensor isconnected to the mainboard by means of a special plug. The cooler is fastened onto the board witha U-shaped spring-clip. Thermal interface, which provides the contact between the heatsink and theprocessor core, is based on the elastomer - rubber-like plate made with heat-transfer additives.

This cooler is very unlikely to provide efficient cooling while the system is working, becausethe thermal interface can't boast high heat conduction and regular surface. Besides, the fan isfastened in the middle of the heatsink, which doesn't guarantee even cooling of the surface: thebest effect is achieved only in the middle part of the heatsink. Moreover, it is also worthmentioning that the use of slider bearings in the fan causes quite a tangible noise and leadsto a relatively short service time.

Highs

• Low cost

Lows

• Relatively small heatsink surface
• Ineffective heatsink cooling
• Elastomer thermal interface pad

TennMax P3 TF Cooler

The remarkable thing about this cooler is that it has two fans on the heatsink providing evenair circulation along the entire surface. Compared to the usual products like that, TennMax P3 TFCooler heatsink has a bit more fins with a special cross-dent serving to enlarge the surface size.Besides, there are also slips for L2 cache cooling, which help to blow enough air onto cache chipsdue to the double-fan construction.

The cooler is equipped with very high-quality fans of 50x50x10mm rotating at about 4000rpm.The outs of both coolers are merged together and they are connected to the mainboard through onesingle plug. However, the rotations rate check is organized only for one fan of the two available.That's why in case the other one stops, system monitoring will be unable to submit a warning message.But, both fans can boast ball bearings, which provide very little noise and guarantee their longendurance.

The cooler is very conveniently fastened to the CPU - by means of two double-position spring clips,fastened to two U-shaped pins inserted into the CPU package. We would like to note here that thistype of cooler retention is more long-lasting than the usually applied spring.

The thermal interface of TennMax P3 TF Cooler is carried out as a specially designed elastomer,which proves much more effective than the other ordinary means. The material starts softening atapproximately 40C, which provides a better mating with the surface being cooled - the processorcore.

Another very attractive peculiarity of TennMax P3 TF Cooler is the possibility to fasten itto the PLGA SECC2 processors, which can be easily put into practice after you take off 4 washersfrom the retention pins.

Highs

• Strong airflow across the heatsink due to two fans
• A very high quality heatsink with a relatively large surface
• Comfortable retention
• Perfect thermal interface

Lows

• Only single fan monitoring

Elan Vital FSCL03-L Cooler

The typical feature of this cooler is its covered design, so that the airflow created by one ofthe fans evenly goes along the entire heatsink surface. Elan Vital FSCL03-L has a bit higher profilecompared to all the other coolers, and a longitudinal fins compared to the cross ones of the othercoolers. However, its surface is just the same as that of TennMax P3 TF Cooler, because the heatsinkfins of Elan Vital FSCL03-L Cooler are slightly finer and hence are made closer to each other. Theadditional surface it the heatsink coverage top.

The Elan Vital FSCL03-L fan, 50x50x10mm, is equipped with one ball and one slider bearing. Therotation rate is about 4700rpm. The fan is connected directly to the mainboard and has a specialrotation sensor. Despite the rubbing of some parts the noise produced by Elan Vital FSCL03-L is thelowest among all the pieces tested.

Elan Vital FSCL03-L is fastened to the CPU by means of closing four built-in pins insertedthrough the CPU coverage with one single spring clip. This retention type also perfectly suitsfor long-lasting connection of the cooler to the processor.

The thermal interface of Elan Vital FSCL03-L is based on the foil covered with thermal pasteto provide a better contact between the heatsink and the processor core. This paste helps toeliminate any cavities between the foil and the surface being cooled. However, this solutionis unfortunately valid for one occasion only, because after the first time used some paste sticksto the CPU surface and remains there. Despite this inconvenience, the foil has a somewhat betterheat conduction than the usually utilized elastomers.

And one more very nice positive feature of Elan Vital FSCL03-L. You can easily find a specialmark on the cooler denoting its upper side. This helps you to fasten the cooling device in thecorrect position from the first time.

Highs

• A very original covered heatsink with larger surface
• High heat conductivity of the thermal interface
• Comfortable retention.

Lows

• No L2 cache cooling
• Use of a special paste in thermal interface, which makes it difficult to use the combinationmore than once

Benchmarks

All these theoretical things are just perfect, but the efficiency of the cooling devices shouldbe regarded only at work. We never disregarded the fact that the cooling quality is vitallyimportant for CPU overclocking, especially for extreme overclocking with the increase of theCPU core voltage. So, we ran a number of trials concerning Intel Pentium III 450 overclockingwith various coolers. Everything was carried out on the mainboard, which allows increasing thevoltage for the sake of better outcome.

While running the tests we were taking the CPU temperature in the meanwhile. Unfortunately,there was no way to measure the core temperature that's why we took the heatsink temperaturevalue very close to the core. Of course, the real CPU temperature will undoubtedly be a bithigher than the figures obtained. However, we arranged the tests in the same conditions for allthree, so that to fairly compare the coolers.

The testing system was configured as follows:

• Intel Pentium III 450MHz CPU;
• ABIT BX6 Rev.2.0 mainboard;
• ASUS V3400TNT graphics card;
• Sound card based on the Ensoniq ES1370 chip;
• IBM DJNA 372200 harddisk;
• 128MB SEC PC-100 SDRAM;
• Windows98.

To take the temperature reached with each cooler separately, we every time ran massive 1demo with software rendering at 800x600 for Quake2, and took the temperature after the demowas over. We repeated each benchmark 5 times, and so, the charts below contain the averagevalue of those 5. The temperature of the environment during the trials was about 28C degrees.

Here you can see the results obtained:

So, we see that the processor temperature gets higher almost linearly, however, if theprocessor core voltage rises, the temperature starts growing a bit more abruptly, so thatthe high-quality cooling becomes of great importance and concern.

In case with the ordinary Noname cooler, we got the processor temperature somewhat 5C higherthan it was achieved by the better products. That's why when the frequency reached 527MHz, thefurther overclocking was forced to stop.

The high-quality coolers we utilized for benchmarking provided better CPU cooling andallowed further processor overclocking at higher power supply, which led to greater processorheating. With regard to the posted benchmarks results, we can say for sure that high-qualitycooling is just irreplaceable especially when it comes to overclocking.

Now let's compare the results of Elan Vital FSCL03-L to those of TennMax P3 TF Cooler.The conclusion, however, is more than evident already: a strong airflow is far not the end.Although Elan Vital FSCL03-L has only one single fan, it still manages to surpass even TennMaxP3 TF Cooler. Besides, we would also like to draw your precious attention to the fact that ElanVital FSCL03-L possesses no L2-cache cooling. But the results it showed in the tests were evenhigher than those of the coolers with the L2 cache airing. And this means only that a free aircirculation provided by the SECC2-cartridge open design is quite enough.

Conclusions

The ordinary coolers provide sufficient cooling of the CPU working in the nominal regime.However, if you are dreaming about overclocking, you'd better think about higher-qualitycooling as well. The benchmarks show that greater processor overclocking in usual conditionsappears possible only due to special coolers. For instance, we managed to overclock IntelPentium III 450 up to 600MHz, which is almost 30%! So, if you are striving for greater systemoverclocking and want to secure your PC from crashing in case the external temperature getshigher, then you shouldn't grudge some additional $30 for a cool Elan Vital FSCL03-L or TennMaxP3 TF Cooler. It's really worth this money, believe us!

Update

Having published an article about coolers, we received a couple of letters from the reps ofthe devices reviewed.

1. TennMax explained that their cooler could prove a bit worse than that from ElanVital probablybecause of the worse thermal interface, i.e. the elastomer user in TennMax thermal interface mightprovide insufficiently tight contact with CPU chip compared to the case when they utilized someheat sink grease. In order to check this statement, we took another look at TennMax cooler, however,this time we additionally used some grease between the cooler itself and Intel Pentium III CPU. Andthe cooler achieved somewhat better results similar to those we saw by ElanVital FSCL03-L Cooler.

2. After that we received another letter from TennMax criticizing ElanVital technology. In particularthey said:

The concern of a free floating conductive foil over the bare die withcapacitors/electronics on its parameter is dangerous. The concern of the floating aluminum foil slidingduring installation, or migrating through thermal cycles could short out the system (catastrophic failure).

Sounds really interesting. In this respect we contacted ElanVital and received the following comments:

The warning from Tennmax is not relevant according to our engineers. The conductive foilis not as "floating" as they think. I think you can see for yourself that the chances of thisfoil migrating are negligible. Especially once the cooler has been attached to the CPU it is impossible tomove.

We understand that it's the unwritten law of the competition to undermine your opponent's reputation atany price. But we decided to post these letters just because they make a quite interesting read.However, we have already expressed our personal opinion on the matter in the article above.

Table of contents: Testing participants     Noname     TennMax P3 TF Cooler     Elan Vital FSCL03-L Cooler Benchmarks Conclusions Update