High-Flying: AMD Athlon XP 3200+ Squares Off Against Intel P4 3 GHz

Athlon XP 3200+: An End To Downward Compatibility?

In the time it took Intel to trade its processor platform three times - from Socket 370 to Socket 423 and now to Socket 478 (with the next socket already in the works) - AMD has steadfastly stuck with Socket 462. For many users, this meant that the window of opportunity to upgrade your AMD CPU stayed open longer than for Intel users.

Quite often, a silvery KT133A motherboard could be upgraded to an eye-popping ratings buster with an XP processor boasting a 2200 rating. At trade shows and events, some of AMD's management quite correctly emphasized the Athlon XP's suitability for upgrades as an advantage over the Pentium 4. So, not only could AMD tout its lower price tag as a selling point, but also its expandability.

Therefore, although socket 462 started out in early 2000, it probably won't be retired from the mass market until late 2004. However, the Athlon has gone through a number of development stages. In 2001, the manufacturing process was refined from 180 nanometers to 130 nanometers; later (in 2002), the FSB clock was increased from 133 MHz to 166 MHz. In late 2002, the L2 cache was doubled, from 256 kB to 512 kB, when the Barton core was launched. And now we've reached the last stage of tweaking: AMD has raised the FSB from 166 MHz to 200 MHz, keeping the L2 cache at 512 kB. Now, with the launch of the XP 3200+, to abide by the doctrine of perfect downward compatibility seems absurd.

This time around, you are not going to get by with just upgrading your CPU. The reason is simple: the only way you'll be able to run an FSB clock of 200 MHz stably is with a second-version Nvidia nForce 2 chipset. Older chipset revisions aren't stable at 200 MHz; we've discussed and demonstrated this problem with Nvidia at several meetings. At the time, Nvidia didn't think that an increased FSB clock was a big deal - at least, until the company came out with another chipset revision that now works without a hitch. Plus, if you want optimal performance, there's no way around a board with a dual-channel RAM interface (read: Nvidia's nForce 2).

The long-awaited, and finally available, VIA KT400A single-channel chipset (not to be confused with the old KT400), with an FSB of 166 MHz, is not a real alternative for confirmed hardware freaks, despite its support for DDR400. At SiS, there's the 748 chipset, which offers single-channel DDR400 and a 200 MHz FSB, but there's one minor problem: there still aren't any boards with this chipset.