ASUS A7M266 Review

by FastSite
01/16/2001 | 12:00 AM

AMD-760 chipset, the first chipset supporting DDR memory, was announced quite a while ago already. However, there were no mainboards on it selling. The only AMD-760 based product, which could be theoretically purchased last year, was Gigabyte GA-7DXC mainboard. But unfortunately, its features were very limited and it supported only PC1600 DDR SDRAM and processors with 200MHz FSB. Nevertheless, as soon as the new year came, the situation started changing. The first fully-fledged mainboard based on AMD-760 chipset appeared in retail stores. However, it turned out not the Gigabyte GA-7DX as everybody had expected, but ASUS A7M266.<%BANNER[article]%>

The history of ASUS mainboards for AMD Athlon/Duron CPUs is very interesting and exciting. As you probably remember, ASUS K7M Slot A mainboard based on AMD-750 chipset appeared not immediately and was selling in faceless white boxes at first. ASUS had to arrange it this way in order to escape the anger of the powerful Intel Company. Nevertheless, K7M was then almost the only mainboard, which didn't suffer any stability problems and showed good performance in all configurations. As a result, ASUS managed to win numerous AMD lovers over to its side. That's why the market welcomed with great enthusiasm the next mainboard for AMD CPUs, ASUS K7V, based on VIA KX133. This board proved up to everybody's expectations and didn't disappoint even the most pretensions users.

As soon as the industry switched over to a new Socket A, AMD processors required new mainboards. And again ASUS appeared the first company to introduce its solution. Note that Socket A mainboard from ASUS, ASUS A7V, turned out the first product in the mainboard market, which allowed changing the processor clock frequency multiplier if it wasn't locked. This added to ASUS's popularity among overclockers. Although the first A7V revisions had a few problems, which couldn't remain unnoticed. Nevertheless, things improved with the time and now you will hardly find anyone who remembers what was wrong with overclocking on the first A7V mainboards.

Now after the official announcement of the new AMD-760 chipset, which supports new Athlon processors with 266MHz FSB and DDR memory, we are all very anxious to see a newcomer from ASUS. This company has long been among the first ones to release new products with excellent consumer qualities, high performance and stability. Once more time our expectations came true: ASUS A7M266 appeared. All we need to do now is to check whether this product by one of the today's market leaders features everything we want. So, this is what the today's review is aimed at.

Closer Look

ASUS planned to introduce three mainboards supporting new AMD Athlon processors with 266MHz FSB almost simultaneously. They should be: A7M266 based on AMD-760 chipset, A7A266 based on ALi MAGiK 1 chipset and A7V133 based on VIA KT133A chipset. A bit later we should also see a new product based on VIA KT266 chipset - A7V266. Nevertheless, it was ASUS A7M266 that turned up ahead of all. Here are the specs of the newcomer:

Well, ASUS family of Socket A mainboard has now got a new member. However, A7M266 is not just a regular Socket A mainboard. Besides the ordinary Athlon and Duron processors, it also supports the so-called Athlon-C, i.e. the CPUs officially working with 266MHz FSB, which differ from their 200MHz fellows only by the clock multiplier. These new processors were announced together with the AMD-760 chipset and are supposed to start selling in the nearest future already. Moreover, all the Athlon processors produced in the future will be also designed to support 266MHz FSB.

As far as the location of the processor socket is concerned, there is nothing we could complain about. Remembering the story of A7V, we had expected A7M266 to have a daughter card with an even larger voltage regulator (since it had to support more powerful CPUs). However, there is nothing of the kind on ASUS A7M266. The power supply circuit is located on the mainboard PCB between the processor socket and the output ports layout going to the case rear panel. The power supply circuit includes several inductances, transistors and 1200uF and 820uF capacitors of a relatively small size. However, we didn't notice any stability problems when testing this mainboard. A7M266 proved really good and highly reliable in all our tests even though the processor power supply circuits didn't seem that at all. But as a result, Socket A feels very good on the PCB and thanks to a lot of free space around it, allows installing massive cooling devices onto the CPU, such as Chrome Orb and Super Orb from Thermaltake.

ASUS A7M266 is equipped with two 184-pin DIMM slots for PC1600/PC2100 DDR SDRAM. We would like to mention that A7M266 was initially planned to come out with 4 DIMM slots that's why the PCB layout was designed in this particular way. But since AMD-760 chipset, our mainboard is based on, can work with four PC1600/PC2100 DDR DIMM modules only if they are registered, ASUS changed its mind and left only two memory slots on the board. In fact, this isn't a big problem, really. 1GB DDR memory modules should become available in the nearest future, that's why you will be able to use up to 2GB of memory with your ASUS A7M266.

Unfortunately, AMD-760 chipset doesn't allow the memory and the processor bus to work asynchronously. So, the memory subsystem will be able to show everything it is capable of only if you use a new Athlon CPU supporting 266MHz FSB. Therefore, you will have to put up with your memory working only at 200MHz (in PC1600 mode) unless the new Athlon processors start selling. Just for your reference: according to our recent tests, the performance of AMD-760 with PC1600 DDR memory appears higher than that of any system with PC133 SDRAM that's why it does make sense to upgrade your memory up to PC1600 DDR SDRAM.

With its A7M266 ASUS followed the good tradition of equipping its recent products with AGP Pro50 slot. Although it has a bit more pins than the regular AGP slot, it is compatible with AGP 1x, 2x and 4x graphics cards. We repeat briefly what the main differences between AGP Pro and AGP 2.0 slots are. On both sides of the regular AGP slot there are additional pins intended for connecting 12V and 3.3V power circuits. The new circuits should sent higher voltage to the graphics card, so that it could consume up to 50W. From the practical point of view, AGP Pro slot allows using professional graphics cards with ASUS A7M266 mainboard. In order to prevent the users from installing the ordinary AGP graphics cards incorrectly into the AGP Pro slot, the first 20 pins are blocked with a special lid. Actually, you may have noticed already that quite many mainboards from different mainboard manufacturers can now boast an AGP Pro slot onboard. We don't think it's just a coincidence. Even though now you can count AGP Pro graphics cards with the fingers of your hand, in the future the situation will definitely change. Take for instance one of the most impatiently awaited novelties of this quarter - NV20. It is rumored to require up to 15W of power and the graphics cards based on it are supposed to be equipped with 128MB graphics memory. That's why it is quite possible that some graphics cards will be designed for AGP Pro slot, because of their high power consumption.

We would like to point out that ASUS moved the AGP Pro slot on its A7M266 quite a while away from DIMM slots so that the graphics card installed into the AGP slot doesn't prevent you from doing whatever with the DIMM modules (which is a problem for quite a number of mainboards, unfortunately). Although moving AGP slot to the left told on the amount of PCI slots on A7M266: there are only 5 of them, and the fifth PCI slot is shared with AMR slot. The IRQ scheme of ASUS A7M266 is quite standard: the first PCI slot shares the IRQ with the AGP Pro slot, the second slot - with the integrated PCI audio, the third - with the AMR slot, the fourth and fifth - with the integrated USB controller. As for ISA slots, there is none of them on ASUS A7M266 mainboard.

A7M266 is of standard size for an ATX mainboard. That is why there shouldn't be any problems when installing it into most PC cases. However, the ATX power supply connector is located not in the most convenient place: between Socket A and the ports on the rear edge of the board right at the AGP Pro slot. Of course, ASUS tried to find the easiest solution, because in this case the ATX power cable is plugged directly at the voltage regulator, which sounds very logical, but isn't that good in reality. In this case, the power supply cable will hang over the CPU and hinder proper cooling.

However, the IDE and FDD connectors are all on their right places according to the ATX specification: in front of the DIMM slots. So, you don't need to worry about the IDE and FDD cables.

The package includes a bracket with a couple of additional USB ports, which should be installed instead of one of the expansion cards into the case rear panel. However, the connector for it is situated on the front edge of the board. It means that the cable will go from this connector right across the entire PC case to the rear panel, which can hardly be called an advantage.

ASUS A7M266 may also have an optional integrated PCI sound controller and a network controller. The mainboard we had at our disposal featured an integrated C-media CMI-8738 sound chip. No doubt, this controller provides much better sounding quality than the AC'97 codec usually used by most mainboard manufacturers on their products. Moreover, C-media controller doesn't load the CPU that heavily when playing the sound. It also supports 4.1-channel output and 3D sound that's why most A7M266 owners should be very happy about the sound quality they get from their ASUS A7M266 mainboard. By the way, when ASUS A7M266 was announced they promised that it would support 6-channel audio systems, however, the developers seem to have forgotten about that. The integrated sound controller can be disabled on the hardware level with the help of a special jumper. Though it should be also possible to disable it via BIOS Setup, this function doesn't work for some reason. There may also be an optional network controller from 3Com on ASUS A7M266 - 3C920. Then there will appear an additional RJ45 connector right above two USB ports on the case rear panel. Unfortunately, the mainboard we had at hand didn't have this controller that's why we can't comment on its functioning.

Like many other manufacturers of AMD-760 based mainboards, ASUS refused to use AMD-766 South Bridge on its product and replaced it with VIA 686B one. So, together with this South Bridge the mainboard received ATA/100 support.

However, ASUS decided to make no use of the hardware monitoring controller integrated into the South Bridge from VIA. As usual, ASUS preferred to rely on its own achievement - AS99127F ASIC chip (Application Specific Integrated Circuit). So, ASUS A7M266 appeared capable of controlling three temperatures. There are not two but three thermal diodes, note that one of them is external and isn't included into the package. The mainboard also controls 6 voltages. Besides, A7M266 features a chassis intrusion detector. The mainboard is equipped with four cooler connectors and controls the rotation speeds of three of them. The fourth connector serves for the North Bridge cooler and even though the cooler itself has a tachometer, the cable is too short to get to any other connector supporting hardware monitoring function.

As for the mainboard BIOS, ASUS A7M266 is based on Award Medallion BIOS 6.0 and its interface is very similar to that from Phoenix. At the same time, the amount and functional peculiarities of the available settings make it similar to the classical Award 4.51PG. We would like to stress here that ASUS is the only company, which took care about a more or less informative help file for its BIOS, making clear some settings to the users.

Like all other recently announced ASUS mainboards targeted for progressive users, A7M266 supports iPanel. Just for your reference: iPanel is a device installed into the 5-inch bay of the PC case and provides easy access to 2 USB ports. Besides, there is also an indicator displaying the POST-codes during the system boot-up and the system status and other parameters, such as CPU and memory frequency, CPU temperature, fan rotation speeds and some voltages. Moreover, iPanel has 5 buttons, two of which allow starting the Internet browser and e-mail client and the other two can be user-programmed for a certain function in Windows.

Besides iPanel, ASUS A7M266 may also support iProbe, the bracket installed into the case rear panel instead of one of the expansion cards and provided with two-digit indicator displaying the POST-codes on system boot up.

Overclocking

Well, it's high time we talked a bit about the overclocking potential of ASUS A7M266 mainboard. Especially, since ASUS promised to devote particular attention to overclocking in its A7M266. In fact, there is hardly anything brand new here. Even ASUS A7V Socket A mainboard based on VIA KT133 chipset featured everything an overclocker may ever dream of. Now let's take a closer look at our A7M266.

Like in all the previous products, ASUS introduced JumperFree technology in its A7M266 as well. ASUS claims that it allows changing the CPU parameters via BIOS Setup. JumperFree mode is enabled by a special jumper on the mainboard, otherwise you should change the CPU parameters only with the dip-switches or jumpers. However, in case of ASUS A7M266 only the FSB frequency belongs to those CPU parameters changed in BIOS Setup. All the other things can be modified only manually with the help of the jumpers or dips.

And now let us say a few words about those parameters, which are subject to changes. Remembering about A7V and its rich overclocking features, we expected A7M266 to let us also change FSB frequency, CPU clock multiplier, Vcore and Vio. However, things turned out not so beautiful, as we had expected. The major disappointment brought by A7M266 was to find out that it didn't allow changing the CPU clock multiplier: this function simply disappeared in some mysterious way. The matter is that the first A7M266 samples (Rev. 1.01) feature a special set of 5 dip-switches intended for changing the CPU clock frequency multiplier in case it appeared unlocked. However, the A7M266 selling now is Rev.1.03 and it doesn't have this notorious set of dip-switches responsible for changing the CPU clock multiplier.

Revision 1.01		Revision 1.03

However, the most remarkable thing about it is that there remained the painted description of these dips on the PCB!

This makes us think that ASUS launched into the market an unfinished product, just the same like in case of A7V, if you remember. Then the first mainboard samples also didn't have the dip-switches serving to increase the CPU clock multiplier. Although they appeared on the further versions of the mainboard. So, we really hope that new revision of ASUS A7M266 will get back its dip-switches and will allow overclocking the CPU by means of increasing the clock multiplier.

As for the other overclocking functions, thank goodness, they are all there. Speaking about the FSB frequency, we shall say that ASUS surpassed everybody here. You can set the FSB frequency in the BIOS Setup equal to any value from the interval between 100MHz and 180MHz with 1MHz increments. We haven't yet seen any other Socket A mainboards offering a range of the supported FSB frequencies that big. Although there is a fly in this ointment: setting the FSB frequency is not the easiest task to fulfill. If you select the corresponding menu item in the BIOS Setup, namely "Set System Operation Frequency", you will get a choice of only two options: increase or decrease the current FSB frequency by 1MHz. That's why setting the FSB frequency to some non-standard value, which is far from the regular 100 or 133MHz may force you to repeat "+ 1MHz" operation many times, which is kind of irritating and boring, you know.

Just out of curiosity we tried to find out what is the highest FSB frequency, which doesn't tell on the mainboard stability. We ran all overclocking tests with a Duron 650MHz, which in other systems proved capable of running at the frequencies over 1GHz when we increased its clock multiplier. What about ASUS A7M266? Here this CPU reached the maximum of 153MHz FSB:

When we added one more megahertz to the FSB frequency, the system crashed.

As for changing processor Vcore, ASUS A7M266 has a special set of 4 jumpers supporting Vcore from 1.1V to 1.85V with 0.05V increments.

Of course, the mainboard also allows changing Vio with the special jumpers. There are two of them now, since the chipset and DDR SDRAM modules require lower voltage now. One jumper is responsible for the voltage supplied to the clock generator and allows increasing it by 0.15V or 0.26V, and the second jumper - for the voltage supplied to the chipset and memory modules permitting the increase of 0.1-0.2V.

So, ASUS A7M266 offers a very rich set of options for processor overclocking with the FSB frequency although it doesn't support clock multiplier modifications. Nevertheless, it isn't a big problem at all. It is much easier to overclock processors by means of increasing the FSB frequency rather than by changing the CPU clock frequency multiplier, since the first option works only with those CPUs featuring an unlocked clock multiplier. Besides, AMD-760 chipset doesn't impose any restrictions over the FSB frequency growth that's why overclocking the CPU with the FSB frequency will provide almost the same outcome as overclocking with the clock multiplier. The only exception here may appear the younger Duron models, which can boast huge overclocking potential. Sometimes we come across such Duron processors, which can work at the frequency over 1.5 times higher than the nominal. In this case it will be really hard to squeeze the maximum out of a CPU like this on ASUS A7M266 mainboard, because at the FSB over 150MHz the system memory, chipset, PCI-devices and AGP graphics cards may cause system instability, for instance.

Testbed and Methods

Well, we have come to the most exciting part of out today's review: the performance. Since ASUS A7M266 is not the first AMD-760 based mainboard in our testlab, we will not dwell on its performance compared with that shown by other platforms. If you are interested in taking a look at AMD-760 + DDR SDRAM compared with other memory types and chipsets, you may take a look at our recent Gigabyte GA-7DX review. And here we will watch ASUS A7M266 against the background of its major competitor - another AMD-760 based mainboard, Gigabyte GA-7DX, which should also start selling in the nearest future. So, there were 4 systems altogether, which took part in our tests:

All the systems ran under Microsoft Windows 98 SE.

Before we pass over to our benchmarks, we would like to make a small comment. According to JEDEC specification, PC2100 DDR SDRAM can have two different CAS latencies: 2 or 2.5. PC2100 DDR CL2 works faster and hence costs more. However, keeping in mind that PC133 CL2 and CL3 perform very close to each other and differ by 2-3% at the most, we decided to tackle the DDR memory and to see what happens with it. Especially, since the difference in the CAS latencies of various PC2100 DDR memory types appeared even smaller than that in case of PC133 SDRAM. The table below shows results obtained on a system with ASUS A7M266 and PC2100 DDR SDRAM with the CAS-timings changed via BIOS Setup:

As you can see from this table, the difference between the systems with PC2100 CL2 DDR and CL2.5 latencies is so insignificant that hunting for the memory with CAS 2 latency doesn't make any sense. That's why the only reason to consider PC2100 CL2 a better memory is its high overclocking potential. Even according to JEDEC, PC2100 CL2 DDR can be easily clocked for 143MHz with the CAS latency set to 2.5.

Performance

We decided not to include too many benchmarks here and would like to dwell on the performance of our today's hero only in typical applications. The thing is that the mainboards tested didn't differ greatly in their performance therefore it would be wrong to focus solely on the numbers.

At first we will take a look at ASUS A7M266 in office applications. We would like to concentrate on the results obtained on a system with PC2100 DDR memory in the first place.

In both Winstone 2001 tests ASUS A7M266 is slightly ahead of the competitor from Gigabyte. In Business Winstone the gap between them is a bit more noticeable, although this 2.5% advantage can hardly be called a significant achievement.

In SYSmark2000, which doesn't load the memory bus so heavily as the previous benchmarks, Gigabyte GA-7DX manages to leave ASUS A7M266 a bit behind.

And now come 3D games.

In 3DMark2000 the results obtained on both mainboards are very similar. However, the higher gets the resolution, the more ahead appears Gigabyte GA-7DX board.

Here the picture is just the same as in the previous case. At lower resolutions both mainboards run almost neck and neck, while at higher resolutions ASUS A7M266 falls slightly behind Gigabyte. Note that in systems with PC1600 DDR SDRAM and processors supporting 200MHz FSB, GA-7DX appears considerably faster than its competitor.

In Unreal Tournament the situation is just the opposite and ASUS A7M266 starts winning about 1.5-2% from its rival.

Mercedes-Bens Truck Racing shows the performance difference between the systems best of all. At lower resolutions it is ASUS A7M266 that wins, while at higher resolutions its leadership is no longer indisputable.

Summing up the results you have just seen, we can state that ASUS A7M266 proves better than Gigabyte GA-7DX in the applications loading the memory subsystem heavily enough. However, when the AGP bus and the graphics subsystem turn out the most heavily loaded parts, Gigabyte makes a tangible dash forward and leads the race. All in all, we wouldn't dare draw any definite conclusions about the performance of ASUS A7M266 compared to Gigabyte GA-7DX.

Conclusion

So, the first fully fledged AMD-760 based mainboard, which appeared in retail, turned out not that bad at all. At least ASUS A7M266 features ASUS's traditional stability and pretty high performance. However, we still have the impression that this product is a bit too raw, i.e. ASUS sacrificed the opportunity to finalize the mainboard before pushing it into the market for the sake of being the first one to start selling. What made us think so, was the strange situation with the dip-switches for the clock multiplier modifications, which are absent on the current mainboard revision (Rev.1.03) for some reason. That's why we wouldn't recommend buying ASUS A7M266 now at least unless ASUS finally settles the mainboard specs. However, since there are no other products on AMD-760 chipset available in the today's market we hardly have any choice. That's why ASUS A7M266 doesn't have an alternative in the meanwhile.

Highs:

• Supports DDR SDRAM and AMD Athlon CPUs with 266MHz FSB;
• Highly stable and reliable;
• Perfect overclocking by means of increasing the FSB frequency;
• Supports iPanel;
• Features an extra pair of USB ports included into the package.

Lows:

• No dip-switches to set the CPU clock multiplier;
• Some design drawbacks.