DDR400 for Athlon: A Comparison of 9 Motherboards

Small Steps: Nine Athlon Motherboards With The KT400 Chipset

The launch of the KT400 puzzled many - when using the much praised new memory (PC3200 standard, a.k.a. DDR400), the new chipset was not one bit faster than its predecessor, the KT333.

It’s been a few weeks, and the manufacturers have had time to optimize their products. A total of nine of the latest boards with the KT400 chipset found their way into our lab to see how they stack up not only against each other but also, again, against their predecessor. We adapted our benchmark tests for this purpose. For the very first time, we ran the tests using memory modules that, at 400 MHz, also handle the fast CL2 mode - with amazing results. In addition, we wanted to be able to draw meaningful comparisons to the KT333, which is why we re-ran all the tests with DDR333 memory. Our reference board with a KT333 chipset was an Epox EP-8K5A2+.

Aside from all the discussions about the performance of the current generation of motherboards, we were happy to see the many features displayed by the test candidates. For example, several USB ports (USB 2.0) and a sound system are part of the minimum. In addition, some of the boards already feature interfaces for Serial ATA hard drives, as well as FireWire or network controllers.

DDR400 Vs. DDR333 : Less Is More

DDR400 memory from TwinMos was available for testing the first KT400 arrivals, but it could not be used reliably with a CAS latency (CL) of 2. We are therefore unable to say whether CL2 would boost performance over CL2.5.

We ran all the tests for this article using a different memory module :

The crème de la crème : PC3200 DDR400 memory from Corsair, CL2-capable.

The operation of this DIMM module, with demanding timing settings, was no problem with most KT400 motherboards. However, we were brought right back down to earth when we realized that even this memory didn’t boost performance much over DDR333 (also with CL2) ; see our benchmark section for more details.

Therefore, the editor’s choice for the most useful memory is definitely DDR333. The modules for operation in CL2 mode are affordable and, by today’s standards, certainly not any slower than DDR400. The latter is still hard to find for CL2.

DDR400 : On-the-sly Support

It’s not a joke. There’s hardly a manufacturer today who officially supports DDR400. VIA’s KT400 white papers only mention DDR333, and SiS has also officially given up on supporting DDR400 for now, not to mention Intel. The additional effort is simply out of all proportion to any potential performance boost... which will be a long time in coming.

But anyone with any self-respect will stay on the ball. For example, the motherboard manufacturers provide DDR400 support. Most of the time it’s officially mentioned in the manual ; at times mention is made of an optional 200 MHz mode (400 MHz DDR), which then remains "unsupported."

The manufacturers shirk their responsibilities with comments like this one : DDR400, yes ; support, no.

All the boards do have one thing in common : the memory clock can be set in BIOS to 133, 166 or 200 MHz, without any kind of warning.

VIA KT400 : Evolution Or Impasse ?

Following the sobering test results of the first KT400 motherboards, voices demanding a revised version became louder. True to VIA "tradition," KT400A is, in fact, right around the corner. The question, however, is : does this step really make sense at this time ? Our current test of the new Athlon XP 2800+ (AMD Travels Through Time : Athlon XP 2800+ with Dual-DDR ) confirms that the new processor represents a respectable leap ahead. This, however, is mostly on account of NVIDIA’s nForce2 chipset, which, thanks to its dual-channel DDR interface, offers substantially more memory bandwidth than conventional systems will ever be able to offer. Consequently, we have set our sights on NVIDIA. Should the (graphics) chip forger finally get going with the nForce2, SiS and especially VIA will be in for some tough times. Right now, none of the products out of Taiwan can measure up to the nForce2 - even if they do slug it out at 166 or 333 MHz FSB.

But the KT400 offers other novelties over the KT333 that justify its existence. For example, it is VIA’s first Athlon chipset with AGP 8x support. What is new, too, is the connection between the Northbridge and the Southbridge, which VIA calls V-Link. Quad-data-rate technology enables KT400 to offer 533 MB/s instead of 266 MB/s.