This is the AMD section of my motherboard chipset information article. AMD Athlon users have many more chipsets available to them than Pentium 4 users, as AMD has used the same socket - Socket A, since the first Athlon Thunderbirds were released. There are currently 2 FSB speeds available for Socket A. The older Thunderbirds (Athlon Thunderbird B) used a 200 Mhz FSB (front side bus). The newer processors use a 266 Mhz FSB. ("200 Mhz FSB" actually runs at 100 Mhz, but delivers twice the amount of data per clock cycle, thus having performance equal to a 200 Mhz FSB. 266 Mhz FSB thus runs at 133 Mhz, but is again DDR (double data rate). In this article I will refer to only 200 Mhz and 266 Mhz to avoid confusion.)
All AMD Durons use the 200 Mhz FSB speed. All Athlon XPs and MPs use the 266 Mhz speed.
All Athlon Thunderbirds below 1 Ghz used the 200 Mhz FSB.
The Athlon Thunderbirds at 1, 1.1, 1.2, 1.3, and 1.4 Ghz were available in both varieties, but the 266 Mhz versions had significantly higher performance. 266 Mhz FSB Thunderbird Athlons were known as Athlon Cs and the 200 Mhz version were Athlon Bs. If you are looking at the processor itself the die has a B or C right after the speed in Mhz on the first line.
There are MANY chipsets available that support the AMD K7 line of processors. I will start out with the older chipsets (many of which are no longer available). Unfortunately since there are so many I cannot possibly cover them all. (I will not be considering any of the older Slot A chipsets for the Athlon A type.)
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VIA:
KT133 - This was the first available chipset supporting the Thunderbird Athlon. It supports only the 200 Mhz FSB and used regular SDRAM. A feature of this chipset was the ability of the chipset to support either PC100 or PC133 SDRAM. Enabling PC133 in the bios increased system performance.
KT133 strengths - Performance of this chipset was very good compared to the older Slot A Athlons previously available. Early compatiblity issues were present that were largely resolved with newer VIA 4 in 1 drivers or bios updates. After the issues were resolved stability was very good to excellent.
KT133 weaknesses - Soundblaster Live! cards can be tricky to setup on boards using this chipset. AGP 4x with fastwrites and sidebanding enabled did not work right until newer bioses and drivers largely resolved the issue.
Kt133 other issues - Only supports 200 Mhz FSB processors. Some motherboard manufacturers released bios updates recently for these boards allowing support for Duron processors at 1 Ghz and greater. (Duron 1 Ghz and up support SSE instructions just like the Athlon XPs, thus requiring SSE support in the bios.) There was a rare offshoot of this chipset known as km133 that included onboard video and sound that was mainly used for integrated low cost systems. Requires VIA 4 in 1 drivers. The chipset allowed multiplier adjustment and FSB overclocking.
The kt133 is no longer in production and it is unlikely any of you will find a board based on this chipset in any computer store.---------------------------------------------
KT133a - This chipset was the first to support the 266 Mhz FSB processors (Athlon C). Performance was improved as compared to kt133, though it still used PC133 SDRAM.
Kt133a strengths - Potentially supports all Socket A processors. (Some early revision Abit KT7a boards do NOT support Athlon XP.) Many motherboards were based on this chipset, which resulted in very good prices for consumers.
Kt133a weaknesses - Most kt133a boards included the infamous 686b southbridge. The 686b southbridge had possible data corruption issues when copying very large files from drives on separate IDE channels when a soundblaster Live! was present in the system. The problem was fixed with a patch from VIA, though the problem was actually largely due to the Soundblaster card itself not fully complying with PCI bus specifications. Potential issues with USB connected DSL modems.
Kt133a other issues - Requires 4 in 1 drivers. Can possibly support Athlon XP and Duron > 1 Ghz processors with bios updates. Extensive overclocking options.
The KT133a is no longer being produced, though you may still find it in stores. I would not recommend it for new systems, as it still uses PC133 SDRAM.---------------------------------------------
KT266 - The KT266 was the first DDR ram supporting chipset for the Athlon series of processors.
KT266 strengths - Improved performance over KT133 and KT133a. Few reported compatibility issues. Very good stability. Supports all Socket A processors. Lower cost than other DDR ram supporting chipsets.
KT266 weaknesses - Performance was not up the same level as other DDR ram supporting AMD chipsets. Numerous 4 in 1 revisions improved performance somewhat, but performance was never exceptional compared to the other DDR ram chipsets for Socket A.
KT266 other important information - Requires 4 in 1 drivers. Supports extensive overclocking options including multiplier and FSB adjustment.
The KT266 is no longer in production, but it's very likely you will still see some motherboards based on it in stores. I would pass them up for better performing models.---------------------------------------------
KT266a - Replaced the original kt266. Offers MUCH higher memory performance than the kt266.
KT266a strengths - Currently the highest performing chipset for AMD socket A processors. Motherboards based on this chipset are priced very well. Stability has so far been superior to all previous VIA chipsets and few compatibility issues have been uncovered. (Only 1 that I know of, and the fix is very simple.)
KT266a weaknesses - Very few weaknesses, but the chipset is still fairly new. VIA track record indicates that some compatibility issues may crop up over the life of the chipset, but so far there have been no significant issues.
KT266a other information - There is a reported issue with GeForce 3 video cards resulting in a minor to significant performance impact. The fix is very simple, go into the bios and make sure the AGP Aperature setting is 128 Mb, and not 64 Mb. Supports several overclocking options. Still requires VIA 4 in 1 drivers, though these have been included in Windows XP. (There are still newer versions available from VIA itself though.)
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ALI:
Ali Magik 1 chipset: One of the first DDR supporting chipsets. An interesting feature was the support for regular SDRAM as well, though this of course resulted in a performance degradation.
Magik 1 strengths - Very good stability with no reported issues. Very good pricing. When using DDR ram, performance was slightly better than the original kt266. Allowed the use of either PC133 or DDR 2100 ram. Supports all Socket A processors.
Magik 1 weaknesses - Performance is not as good as some newer Socket A chipsets.
Magik 1 other information - Ali does provide new chipset drivers, but as there are no (at least that I know of) reported issues with this chipset they are rarely updated.
Even though boards based on this chipset are very stable and still available, I would not recommend it for a new system. There are better performing options now available. ALI is reported to be working on a new version of this chipset with improved performance.---------------------------------------------
AMD:
AMD 760 - This is a socket A chipset directly from AMD itself. AMD has now ended production of this chipset, but many boards still use it.
760 strengths - Perfect stability record. There are no confirmed issues with this chipset. Performance is better than the kt266 and Ali Magik 1, but newer chipsets are faster.
760 weaknesses - Expensive compared to other Socket A chipsets. Only supports 2 ram slots, limiting maximum RAM size.
760 other information - AMD does provide drivers for this chipset on their website, though they are only updated rarely. Supports all Socket A processors. Does not support overclocking to any significant degree. Some boards using this chipset use a VIA southbridge to reduce manufacturing costs, meaning some VIA drivers are neccessary, though generally only the version that came on the included CD with the motherboard are neccessary.
The AMD 760 is no longer in production. Although newer and slightly better performing chipsets are available, the proven stability and good performance of this chipset still make boards based on it highly sought after. AMD 760 based boards are still a good choice, but arguably not the best available anymore.---------------------------------------------
AMD 760 MP - Nearly identical to the regular 760 chipset, but supports dual processors. Only one manufacturer, Tyan, made boards with this chipset. Boards using this chipset are expensive, but they certainly are some of the most stable motherboards currently in production - be it Intel or AMD supporting. These boards have gained some significant market share in the workstation and server market.
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AMD 760MPX - This is a new updated version of the 760MP chipset. It also supports dual processors, but adds support for such exotic devices as a 66 Mhz 64 bit PCI interface cards. (Important for workstation and servers.) Stability should be absolutely top notch, though price will undoubtedy be very high. Asus has recently announced a consumer level board based on this chipset, the A7M266-D. If you use 2 Athlon 1900+ MP processors this is for the most part the highest performing x86 based configuration available. (Slightly exceeding or matching the dual processor 2 Ghz Pentium 4 Xeon i860 based systems.) The cost for building a system such as this can easily top $3000. As can be imagined cooling and power requirements are extreme.
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Nvidia:
nForce 420 - A brand new chipset released by the same company that makes the GeForce series graphics processors. This chipset is nearly identical to the one that powers the new Microsoft XBOX gaming console. Revolutionary in many ways, only nVidia's recently entry into the chipset market makes its future unknown.
nForce 420 strengths - Very high performance, nearly the same as the VIA KT266a, though it is likely that future bios and driver revisions will make it the highest performance single processor chipset available for AMD processors. Supports Dual Channel DDR ram, delivering the highest memory bandwidth available on any PC platform. (RAMBUS PC800 is 3.2Gb/s, dual channel PC2100 is 4.3 Gb/s.) This extra bandwidth can potentially speed up the system in data transfer and AGP mode memory access. Integrated GF 2 Mx 400 graphics and SB Live! Platinum quality sound make this a potentially very useful platform for inexpensive computer upgrades. Early stability reports have been flawless, and there are absolutely no compatibiltity issues. The nForce chipset also includes a hardware prefetch unit into the chipset itself, which can increase performance significantly in certain applications. Supports all current Socket A processors.
nForce 420 weaknesses - Only 2 motherboards currently available using this chipset, both are expensive. (Asus A7N266 and MSI K7N420 Pro) Only supports 1.5 V AGP cards, though any AGP card that is not 1.5 V operation is not as fast as the integrated GF 2 Mx core. Nvidia has an unknown track record in the chipset market, though the fact the chipset is used in the xbox (only difference is integrated GF 3 graphics and a P3 733) indicates extensive testing has been done.
nForce 420 other imporant information - Supports only minimal overclocking options. The MSI board also has integrated ethernet. The integrated sound has front and rear speaker outputs and a SPDIF digital output for Dolby Digital 5.1 capable receivers. First hand experience tells me sound quality is absolutely excellent. (See my post in this forum.) Onboard sound currently does not support EAX (Creative Soundblaster) surround modes, though nVidia claims future drivers will resolve this.
This chipset, although still very new, has shaken up the chipset industry. My own first hand experience with the MSI board (and also the experience of most reviewers) was that this board has absolutely top-notch stability and setup was extremely easy. Unless you want lots of overclocking options, I'd recommend this chipset highly.nForce 220 - Same as the 420, but without the dual channel DDR support. No current motherboards use this chipset.
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SIS:
Sis 735: The only DDR supporting chipset from Sis. Very few boards use it.
Sis 735 strengths - Very fast performance, though not as high as kt266a or nForce 420. Low price. Good stability. Currently supports all Socket A processors.
Sis 735 weaknesses - Since so few boards are available using this chipset long term reliability may be in question. As far as I'm aware only ECS (Elitegroup) has a board using this chipset.
Sis 735 other information - Drivers are available from SIS. For a short time this was the top performing Socket A board, but unfortunately for SIS, VIA released the kt266a very soon after this chipset was released and reclaimed the performance crown. This cooled enthusiasm for this chipset significantly.
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My personal recommendations, should you choose to go the AMD route depend on whether you want overclocking options or not. If overclocking is not desired I'd choose either a VIA kt266a, Nvidia nForce 420, or AMD 760 based board. If overclocking abilities are desired the VIA KT266a chipset is the only real option. (It is important to note that starting with the newest XP 1900+ processors AMD has eliminated the possibility of connecting the L1 bridges that allowed such easy overclocking of the Thunderbirds. Even the "older" Athlon XPs had laser cut bridges that are much harder to connect than the original Thunderbirds.) The SIS 735 is not a bad choice, but unfortunately no major manufacturer offers it and since it no longer holds the performance crown, low cost is its only remaining highlight. Future bios and driver releases will likely make the nForce 420 the top performing AMD Socket A chipset.
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For more information
www.anandtech.com and
www.tomshardware.com are both useful resources.
Comments and feedback are welcome.
