Motherboard guide - AMD

This motherboard guide will take you through all the chipsets, but not individual boards - that is up to you. If you do need further advice, don't hesitate to contact me. I will compare them based on features, performance and cost, and split them into the stages of processor development. I will also look at the future chipsets and chips that should be available soon. Finally, I will conclude and suggest a chipset for each possible market.
Early AMD XP chips - 133 bus (xp1600 to 2400)
Next AMD XP chips - 166 bus (xp2500 to 3000)
Last AMD XP chip - 200 bus (xp3200)
AMD Hammer chips - the Athlon 64 and FX-5x series, 200FSB

AMD Athlon XP

The very first XPs came out on a 133 frontside bus. Though quite a few SDR memory based motherboard can potentially run these, i will not be including them due to the severe drop in performance and lack on availability. Plus the newer DDR chipsets are very cheap now anyway.
AMD 750 and 760
Single channel DDR 266, AGP 4x, USB 1.1, UDMA100
The first ever true XP platform, due to the delays in the KT266 series, and pretty much the worst performing. Due to its age, it only just supported the features that others did with the newer 760 design. Stable and simple, but costly and no chance of overclocking.
Once the KT266a came out, the AMD chipset swiftly died. AMD said they would never release a chipset again and concentrate on the processor instead. However, it lived on as the only MP platform for XPs, and many versions came out that added further speed and features.

Via KT266 and KT266a
Single channel DDR 266, AGP 4x, USB 1.1, UDMA100
This chipset was the first DDRram from the AMD partner VIA. The early KT266 was plagued by problems and released in very few numbers. The much more stable and compatible KT266a was a much more capable chipset, and at this early stage in the XPs life was the chipset of choice due to performance, stability and compatibility.
Most motherboards on this chipset came with onboard sound and some had 10/100 network. Other additional features such as IDE Raid were rare. Firewire, USB2 and other such connections were rare

Dual channel DDR 266, AGP 4x, USB 1.1, UDMA100
A late entry to the market, and a first for NVIDIA was the Nforce chipset. Designed as an all-in-one board but with a high price, it came with excellent sound, networking and reasonable single channel performance. But where it really excelled was when dual channel was enabled by using two identical memory chips in the right sockets. This made little difference in most situations, but heavily memory-orientated tests showed a reasonable difference.
Another great addition was the optional onboard video. Though it took away most of the performance difference in dual channel and killed the performance in single, because it was based on the GF2mx it provided a stable complete windows computer right out of the box. Not too good for games at the time, but a good general workhorse.
Sadly, few motherboard makers used this chipset until it was too late, and most came out as an overpriced jacks-of all-trade. Due to the new design and first entry it had a few problems, but most were fixed over the chipsets lifespan.

SIS 735
Single channel DDR 266, AGP 4x, USB 1.1, UDMA100
SIS are known for their value chipsets, and the 735 was no exception. Not the best on performance, features or compatibility, but you could not beat the price. Generally, it came with sound and sometimes networking a good few tenners below the competition. It came out before the KT266a and beat the AMD 760 and KT266, so was the platform of choice for little while, mainly due to its combined north and south bridge improving communication speed as well as reducing cost.
Some of these boards came with both SDR and DDR sockets, which meant you could upgrade to a XP for little cost and replace your slower memory later when prices drop. But due to its lacklustre performance and value name, it was never utilised much in the market besides a few instances. Some people recognised its bang-for-the buck, but it never made it as a serious contender.

SIS 745
Single channel DDR 333 (async), AGP 4x, USB 1.1, UDMA100
To combat the arrival of the KT266a, SIS simple added ddr333 support and the ability to run the memory quicker than chip. It did increase performance a bit, but never enough to grab the market like the 735 briefly did.
Once again, you could not beat the value in this little package. But without the latest features including the new 166 fsb, it was left in the dust.

Next AMD XP chips - 166 bus (xp2500 to 3000)

To improve scalability and performance, AMD moved their production to a smaller size (0.13 micron) and upped the frontside bus to 166. Though the new die size was compatible directly, none of the current chipsets officially support a 166bus. So they started creating new ones, adding the latest features as well.
Via KT333
Single channel DDR333, AGP 4x, USB 1.1 and USB 2, UDMA 100 and UDMA133
The KT333 was one of the first boards to support the newer 166 bus. Via did little else on top of the successful kt266a except add DDR333 memory support. Later on to keep up with the features on alternative chipsets, they added a new Southbridge with USB2 and UDMA 133. Most boards came with networking and simple sound onboard.
Because of the competition that came later, this chipset became the cheap and low performance alternative to the more powerful and feature packed alternatives.

Via KT400 and 400a
Single channel DDR333/DDR400 (400a), AGP 8x, USB 2, UDMA133, SATA (some 400a)
The confusingly name KT400 suggested a 200 bus speed, but alas it had none. Named purely for support for DDR400 which it did not actually support properly until the 400a revision. It kept the features from the later versions of KT333 and added agp8x, and later the final version of the 400a added SATA support.
Even with the added features, without a dual channel memory controller it could not keep up with the competition. Still a value alternative due to its abundance of features and low cost in comparison.

SIS 746/fx
single channel DDR333/400(FX), AGP 8x, USB2, UDMA133
Most people were expecting the 746 to be a small improvement over the 745, due to the small code increase. In fact, SIS surprised them all by pretty much matching the KT333 specification. Moving back to the traditional north/south configuration and later adding DDR400 support with the fx, they pretty much matched the KT400a apart from SATA.
SIS have never held the performance crown, but they are very good at turning out reasonable performance low price chipsets, and the 746 is not exception. In most cases, it even unofficially supports 200fsb chips unlike the kt400a.

NVIDIA Nforce2
Dual channel DDR400, AGP 8x, USB2, UDMA133, Firewire
Still really holding the performance crown with their dual channel memory controller on the original Nforce, and having substantially interested the motherboard manufacturers with it, the new Nforce2 took top honours yet again. Doing a lot more than just upping the bus speed and adding ddr400 support, they also designed their own networking (and an optional 3com), increased the optional onboard graphics from a GF2mx to a GF4mx and added AGP8 and USB2. The top end Southbridge version has high quality sound and Firewire support directly. The only thing missing was SATA, which most manufacturers added with a third party chip.
Though the dual channel controller and superb (compared to the competition) optional onboard graphics put them head and shoulders above the competition, it all came at a high cost originally. Over time, prices came down and now they are within a few pounds of each other - a good board can be bought for around ?50 and high spec ones are still well below ?100. A good AMD system is not complete now without a Nforce2 board at its heart.

Last AMD XP chip - 200 bus (xp3200)

To add a last burst of performance, AMD upped the final chip to 200fsb. Once again, the chipsets currently available could not (officially) handle the increased bus speed and redesigned their current ones to compensate. Even without an official 200fsb chip, the addition made overclocking higher easier and more production of performance.
Via KT600
Single channel DDR400, AGP 8x, USB 2, UDMA133, SATA
Since the KT400 had already taken the logical name for a 200fsb chipset, Via simply slapped a couple of hundred on to produce the kt600. Pretty much, it is just a kt400 that will run at 200fsb and more, with the latest Southbridge that adds native SATA.
Once again, it had to be designed for the value market as it still kept the single channel memory and could not compete with the powerful nforce2. As a result, they are available fully featured for less than ?50. But the platform of choice for performance will still be Nforce2

Via KT880
Dual channel DDR400, AGP 8x, USB 2, UDMA133, SATA
Recycling the memory controller from the Pentium 4 pt880, Via finally got a dual channel memory chipset out. They also added optional gigabit networking, and only 7.1 sound. It stands a little above the Nforce2 on paper - support for 2G dimms, 4 sockets and native SATA, but it does lack the native Firewire of the nforce2. In performance, both chipsets are near identical.
Since this chipset has only just arrived, we have to wait until boards come out until we can see how the chipsets will compare on price. In theory, the via chipset should be cheaper due to integrated SATA - Nforce2 boards have to add a 3rd party chip which adds a bit to the price. And being so late to market, will manufacturers want to bother with it?

NVIDIA Nforce2 ultra 400
Dual channel DDR400, AGP 8x, USB2, UDMA133, Firewire
The ultra 400 is not a new chipset really, it is just tested for 200 operation and sold accordingly. No new features or enhancements beyond which the manufacturers add to their boards themselves. The cost difference is almost nil as well.
There is also a Nforce2 400, but it is a rare sight indeed. Look out for this one - it lacks the dual channel and is intended for the value market. Don't buy this one accidentally if you are looking for the ultra 400.


If what you want is performance you would have to choose either a Nforce2 ultra 400, or a via PT880 (which are not available yet). For value, you can either fork out a little more for a less feature packed version of the above, but if you are on an extreme budget you have a wide range of choice for single channel chipsets. The KT600 will probably be the best choice, since it will support 200fsb chips for certain, and has native SATA. I have not yet seen a single channel Nforce2, but if prices are lower it could be the better choice since performance is near identical, usually slightly higher. For severe budgets (under ?30) you could opt for an earlier Via chipset and forget 200fsb (e.g. late 400a with SATA) but the SIS 746fx may be a better choice if you want at least the possibility since reports are that most can make it to the magical 200fsb.

AMD Hammer chips - the Athlon 64 and FX-5x series, 200FSB

The Hammer series is a big jump in computing technology. There are two main big differences for chipsets - first, the memory controller is actually in the processor, meaning super low latencies and big performance, but also no memory controller in the Northbridge is required. The second is the change to hypertransport by AMD - the connection between the bridges and the processor itself has been increased in bandwidth substantially so that the demands of AGP, memory and other traffic do not overflow the connection resulting in reduced performance.
Via K8T800
800HT link, AGP 8x, USB2, UDMA133, SATA
The second chipset to come out for the Hammer processor series, but the first with a full 800mhz HT link for best AGP and other device performance. It will work with either the 754pin A64 and the 940/939 pin FX5x series. In most benchmarks, it tends to be between the Nforce3 and the SIS 755, but differences are small due to the removal of the memory controller from the situation. It uses a traditional north/south bridge controller, but the link between them is slow and probably is what gives the sis 755 the marginal lead. A new south bridge with 4 SATA connection and raid is expected soon. Gigabit networking is an optional part of the chipset as well.
One of the biggest problems is its complete lack of pci/agp lock (also not included on XP chipsets), which the competition both have.

NVIDIA Nforce3 150
600HT link, AGP 8x, USB2, UDMA133
The Nforce3 is a case of work in progress. To ensure stability, it only runs a 600Mhz HT link, resulting mostly in slightly decreased AGP performance, though the difference is marginal. It still lacks SATA, and has only 10/100 networking. On the horizon is the 250 and 250pro - upping speed to 800 (and possibly 1000), adding 4 SATA RAID ports and in the case of the pro version, gigabit networking.
Unlike the Via chipset, it has a agp/pci lock which should improve overclocking ability - pity the chipset can't handle much. It was the first chipset for Hammer chips - which may explain its lack of completeness. It does, however have a single bridge chip, removing the latency of a north-south link. Unlike earlier Nforces, it has no graphics option - this is down to the movement of the memory away from the chipset. It still has excellent sound, but the opposition also do now.

SIS 755
800HT link, AGP 8x, USB2, UDMA133, SATA
A recent addition to the market and only exists as production samples at the moment. Using full speed HT link and a 1GB link between its north and south bridge means high performance, but once again marginal compared to the others. It has all the features except gigabit networking, but only 2 SATA RAID so far. It also has the ability to lock PCI and AGP, but production samples are inadequate to test the overclockability.
It does however have one problem - the dual channel design of the FX chips will not be used, the chipset can only use single channel. For the A64 though, it is perfect. A 755fx has been announced, which not only adds dual channel ability, but also a 1000HT link for future chips.


There is a limited choice of chipsets for the Hammer so far. For the dual channel FX, it can only really be the VIA K8T800 due to the 755s lack of dual channel ability and the Nforce3150s small AGP deficit. For the Athlon 64, the SIS 755 should be the winner, when it arrives. The K8T800 since it is available now is the best current choice.
Information on the Nforce3 250 is still scarce, but there is a chance it could take back the crown for NVIDIA. Only time can tell.

Last modified: 01/06/2005