The Three Musketeers — Athlon Platforms For 133 MHz FSB — THG.RU

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Athlon Platforms For 133 MHz FSB» —>

Introduction

It’s no less than 2 months ago when AMD officially announced Athlon processors that run at a processor bus clock of 133 MHz. Previous versions communicated with the system at a clock of 100 MHz, which offers a data bandwidth of 64-bit/8-byte x 100 MHz x 2 = 1600 MB/s, due to the fact that Athlon’s processor bus is ‘double-pumped’, which is why this bus is commonly referred to as a 200 MHz bus.

The ‘new’ Athlon, which can be recognized by the ‘C’ in its name, communicates with the system at a ‘double-pumped’ 133 MHz, improving the interface bandwidth to 2100 MB/s. Since October 30, 2000 we have published benchmark data of systems with the new 133 MHz FSB Athlons on numerous occasions, making it a well-known fact that Athlon-systems are definitely benefiting from the higher bus clock.

Waiting For Santa …

Unfortunately those Athlon-C processors have hardly been made available to the public yet. The most important reason for this annoying delay was the lack of availability and reliability of chipsets that would support the new version of the AMD-processor. Initially the only chipset supporting 133 MHz processor bus clock was AMD’s very own 760 chipset. This chipset does not only provide the 133 MHz bus, but also the support of DDR-SDRAM, a memory type that also offers 2100 MB/s peak bandwidth, making it the perfect partner for the 133 MHz-Athlon processors. Unfortunately AMD ran into some motherboard design problems with this chipset, which is why there’s still no official AMD760-platform with support of 133 MHz processor bus available in the market.

We provided an extensive review of the new Athlon-version plus AMD’s 760 chipset in our article «DDR-SDRAM Has Finally Arrived«.

Waiting For Santa, Continued

The second player in this new arena was ALi with its MaGiK1 chipset. Similar to AMD’s 760 in terms of specs, it supports the new processor bus clock as well as DDR-SDRAM. We refrained from reviewing platforms with this chipset so far, because the performance we saw was hardly worth talking about. Motherboards with ALi’s MaGiK1 chipset are finally becoming available these days and the product has matured a bit, so that we decided to include MaGiK1 in this review.

Since its impressive success in 1999 and 2000, VIA was expected to be one of the first chipset makers to provide a platform for the 133 MHz-FSB Athlon. It’s commitment for DDR-SDRAM generated big hopes that this new chipset would come with DDR-support. Unfortunately it turned out that neither of those hopes would come true. VIA was the last of the three that came up with a chipset that supports the ‘Athlon C’ and this chipset does still not provide DDR-support. In fact, the Apollo KT133A is simply a minimally changed version of VIA’s well-known Apollo KT133 chipset that is now certified to run the processor bus at 133 MHz reliably. I will have to disappoint those of you, who might expect that KT133A-motherboards would become available very soon, because it seems as if a missing design spec from AMD will force most motherboard makers to redesign their KT133A motherboards. My information says that none of those boards was designed to support a maximal processor current of 46 A for Athlon processors at beyond 1500 MHz, because AMD supplied this spec too late.

SDR-SDRAM vs. DDR-SDRAM

Theoretically DDR-SDRAM provides double the bandwidth of normal SDRAM. At 100 MHz memory clock it’s able to supply a data bandwidth of 1600 MB/s, at 133 MHz it goes up to 2100 MB/s. That is why ‘Team DDR’ decided to call the specs of those two DDR-memory types ‘PC1600’ and ‘PC2100’. However, I have to disappoint you, if you should think that DDR-SDRAM is simply twice as fast as SDRAM at single data rate. The basic reason is rather simple. While DDR-SDRAM is indeed able to provide double the peak bandwidth of normal SDRAM, it has still the same (CL2 DDR-SDRAM) or even a slightly worse latency (CL 2.5 DDR-SDRAM) than its older sibling. The result is that in worst-case situations DDR-SDRAM can be as slow or even slightly slower than normal SDRAM. At the same time DDR-SDRAM can easily outperform single data rate SDRAM under ideal conditions. In average, systems with DDR-SDRAM are most certainly faster than systems with normal SDRAM, but the gain depends on the application and can hardly ever reach more than 20%.

We have provided an article with more information about DDR-SDRAM a few months ago and you will also find a very interesting technical write-up about the memory situation at Kyle Bennett’s HardOCP.

Three Different Chipsets

AMD’s 760 chipset is pretty well-known these days, although it is hardly available. It supports AMD’s Socket-A processors Athlon and Duron at processor bus clocks of 100 and 133 MHz. Additionally it provides DDR-SDRAM support. So far it is the fastest Athlon/Duron chipset to date.
<img=amd760-diagram.jpg

While AMD designed the 761 north bridge as well as the 766 south bridge with ATA100-support and other goodies, you will find that most motherboards will team up the 761 north bridge with VIA’s 686B south bridge instead, which is supposed to have less compatibility problems than AMD’s 766.

ALi’s MaGiK1 chipset comes with support of AMD’s Socket-A processors for 100 as well as 133 MHz processor bus as well and it can be teamed up with PC66/100/133 SDRAM as well as PC1600 or PC2100 DDR-SDRAM.

The north bridge of this chipset is the M1647 chip. Below you find the block diagram.

The south bridge of MaGiK1 is the M1535+ chip, which, amongst other things, also offers ATA100 support.

VIA’s Apollo KT133A is not exactly a newcomer. We know this chipset as Apollo KT133, found in the vast majority of SocketA-motherboards that are available. Now VIA was finally able to add support of the faster processor bus and called it Apollo KT133A. This chipset is the only in this test which does not support DDR-SDRAM.
<img=kt133adiagr.jpg

It will be teamed up with VIA’s VT82686B south bridge, which also features ATA100-support.

The Boards

AMD760 — MSI K7 Master

MSI provided us with its upcoming MS-6341 K7 Master motherboard. It optionally features on-board Ultra 160 SCSI with Adaptec’s AIC-7899G-chip and our board came equipped with that too. Basically the MS-6341 is probably the best equipped Athlon-motherboard I have seen so far. Besides the optional on-board SCSI it comes with four DDR-SDRAM DIMM-slots, one AGP-slot, five PCI-slots, one CNR-slot, on-board AC97 audio and MSI’s Smart-D LED diagnostic feature. As most other AMD760 motherboards it is equipped with VIA’s 686B south bridge chip with ATA100 support.

The BIOS-setup allows the alteration of the processor bus clock in small steps and it also lets you overclock the SocketA processors once you closed the L1-bridges on the CPU. Unfortunately MSI forgot to include an option to lower the CPU-multiplier, which would be very useful for owners of 100 MHz FSB Athlon or Duron processors that want to run their CPUs at 133 MHz FSB.

The board provided very stable operation and excellent performance, but the pre-release BIOS has got a problem with the ATA100-feature, as I was unable to get to a higher hard disk data transfer rate than 15 MB/s. I am sure that a new BIOS will remedy this problem, which forced us to use an external Promise Ultra100 IDE-controller for our benchmark runs.

ALi MaGiK1 — Iwill KA266 Rev. 1.1

This is the second KA266 board from Iwill that we received. The first revision was unfortunately not providing very good benchmark results, which was the reason why I refrained from reviewing it at that stage. The new revision 1.1 and the latest BIOS from December 8, 2000 provides improved performance, so that it finally makes sense to test this motherboard.

It comes equipped with three DDR-SDRAM DIMM-slots, one AGP-slot, five PCI slots, and an excellent on-board C-Media(r) CMI-8738 3D audio chip. The BIOS allows overclocking in all flavors. The processor bus clock can be changed in small intervals and the CPU-multiplier can be adjusted to any value between x5 and x12.5. Therefore it is a very handy platform to owners of 100 MHz FSB Duron or Athlon processors who want to run their processors at 133 MHz FSB.

While you will see that the performance of the KA266 is unable to reach MSI’s K7 Master, the Iwill board performed pleasantly stable without any flaws or problems. The ATA100 feature of the ALi M1535+ south bridge chip worked flawlessly and provided a slightly better performance than we have seen with VIA’s 686B south bridge chip so far.

VIA Apollo KT133A — Asus A7V133

On the first look you won’t be able to spot any difference between Asus’ new A7V133 and the well-known A7V. This is obviously not very surprising, since the only hardware difference is the VT8366A north bridge chip, which enables 133 MHz FSB. Once started you find that the BIOS-setup has become more comfortable though. It is possible to change the processor bus clock in 1 MHz steps and now the processor multiplier does not need to be altered with the jumpers, but can be chosen in the BIOS-setup between x5 and x12.5 as well.

The board comes equipped with 3 PC133 SDRAM DIMM-slots, one AGP-slot, 5 PCI-slots, one CNR-slot, on-board AC97 sound and an additional ATA100 IDE/RAID0 chip from Promise, allowing the board to run with up to eight IDE hard drives.

While the A7V133 can obviously not compete with DDR-SDRAM platforms it makes an excellent overclocking platform. You will see in the benchmarks that Athlon benefits from the 133 MHz processor bus quite a bit and so you can already achieve a performance boost if you only run your Athlon 1000/100 at 1000/133 MHz instead, without even overclocking the processor. The missing DDR-support can be seen as a benefit as well, since it enables you to still use your PC133 memory.

The A7V133 turned out to run as stable and reliable as we are used to from the A7V. It was an excellent platform to bring Athlon up to 1500 GHz together with the Vapochill. The same is valid for the other two motherboards as well though.

Test Setup

Benchmarks

Sysmark2000 / Windows 98

The MSI K7 Master is the clear winner of this benchmark, showing that AMD760 plus DDR-SDRAM is currently the fastest Athlon platform available. Obviously the A7V running Athlon at only 100 MHz FSB is the worst performer, but you can see that even office applications are able to benefit from the 133 MHz FSB even if normal SDRAM is used, since the A7V133 is clearly faster than its older brother. The Iwill KA266 with ALi’s MaGiK1 chipset cannot convince in this test. Although it is using DDR-SDRAM it is hardly faster than the A7V133 with normal SDRAM. It is also lagging quite a bit behind the K7 Master with AMD760 chipset.

Quake 3 Arena / Windows 98

In the memory and processor bus intensive 3D game Quake 3 Arena Iwill’s KA266 with ALi’s MaGiK1 chipset and DDR-SDRAM is able to pull away from the A7V133 with VIA’s KT133A and SDRAM. However, the K7 Master with AMD760 and DDR-SDRAM is still the clear leader. Once more it seems obvious that ALi’s MaGiK1 chipset cannot really take proper advantage of DDR-SDRAM.

Flask MPEG Athlon-Optimized / Windows 98

The picture in Flask MPEG video MPEG4 encoding is similar to the Quake 3 result. Once more the AMD760 w/DDR chipset rules this benchmark, while the old KT133 with SDRAM is the slowest. The faster processor bus of the KT133A w/SDR is already able to improve scores a bit, although the memory bandwidth is the same as with KT133. The ALi MaGiK1 w/DDR is able to beat KT133A w/SDR, but it lags quite a bit behind AMD’s 760 chipset.

Pure Memory Performance

There is no surprise to see the A7V and A7V133 perform significantly worse than the other two in this test, as those two motherboards are only using normal PC133 SDRAM. However, you can see that the K7Master with AMD760 chipset is able to get a lot more out of DDR-SDRAM than the Iwill KA266 with ALi MaGiK1 chipset. Again you wonder if MaGiK1 is indeed that magic at all, since it just cannot reach the memory performance of AMD’s 760 chipset.

Summary

One thing is for sure; Athlon is definitely gaining quite a bit of performance once running at a 133 MHz processor bus. Even if teamed up with normal PC133 SDRAM only, the AMD processors are able to gain a few percentage points.

Of course the story looks a lot better with DDR-SDRAM, because this memory type offers the same peak bandwidth as AMD’s SocketA processors. The performance difference between AMD’s 760 chipset and ALi’s MaGiK1 however shows that DDR alone doesn’t necessarily buy you a whole lot of performance. While AMD760 provides quite a significant performance boost in most applications, ALi MAGiK1 is not able to make proper use of the benefits of DDR-memory.

Right now platforms with VIA’s Apollo KT133A chipset might not be able to provide the highest performance, but owners of PC133 memory could use those motherboards as excellent overclocking platforms at the price of a new motherboard.

People who want to get the most out of their Athlon or Duron processors will have to invest into DDR-SDRAM. If you then have the choice between AMD760 and ALi MaGiK1-platforms, you should obviously go for the AMD760 chipset. However, right now neither seem to be available and it looks as if ALi MaGiK1 motherboards will hit the shelves earlier than boards with AMD760. So if you can’t wait, you might have to go for the slower chipset. I personally would wait for AMD760.

Iwill and ALi have already improved the performance of the KA266 since I received my first sample. Maybe there is still room for more tweaking and MaGiK1 will finally live up to the expectations. Right now I don’t foresee a particularly bright future for this chipset.

What we are still waiting for is of course VIA’s KT266 chipset, which will finally provide VIA’s own DDR-solution for Athlon. Maybe it will even be able to compete with AMD’s 760 chipset, but so far I don’t even know when it will be released.