In June 2001, AMD introduced the Athlon MP CPU and the AMD-760 MP chipset to support it, giving AMD its first line of SMP products. The new chipset offers an advanced cache coherency protocol that lets the two CPUs get cached data directly from each other, instead of writing to and reading from main memory. Each CPU has a dedicated 2.1GB/s EV6 bus to the North Bridge.
AMD is also working with the major Linux distributions to do ports to its upcoming backward-compatible 64-bit x86-64 architecture. Wayne Meretsky, an AMD fellow in charge of AMD's Software Research and Development Organization, says that some of the company's work on software optimizations for x86-64 will apply to Athlon too, since x86-64 will continue to support all the 32-bit x86 instructions.
Tyan's Thunder K7 is the first AMD-760 MP motherboard. This large board is the bastard spawn of a high-end workstation board and a low-profile server board—with the AGP Pro slot of the former and the onboard video, SCSI and dual Ethernet of the latter. Rick Moen calls it a “damned fine motherboard”. Either Tyan designed this thing just for an Ultimate Linux Box with both server and workstation capabilities, which seems unlikely given how few people have the good taste to build an Ultimate Linux Box, or they really wanted to get both a server board and a workstation board to market right away. The onboard SCSI is the equivalent of an Adaptec 39160—two Ultra160 buses. As I write this, streetprices.com is listing the Thunder K7 for about $400 US, which sounds outrageous for a motherboard, but it's not too bad for a motherboard, an Adaptec 39160 and a dual Ethernet card.
Beowulf expert Robert G. Brown of the Duke University Department of Physics tried out a prerelease dual Athlon board for scientific computing, and he said, “When two memory-intensive tasks were run at the same time, it exhibited some memory bus binding, but with about a third more effective memory bus bandwidth to dispose of and AMD's generally superior memory management system, it soundly outperformed dual PC133 systems on similarly memory-bound tasks.” (Duke's Beowulf site has benchmarks; see Resources.)
You might want to drill one of your front-panel faceplates to mount extra LEDs. Tyan thoughtfully offers an extra connector for a front-panel “network activity” LED, in addition to the link and activity LEDs in back.
The Thunder K7 is an Extended ATX board, measuring 12 x 13 inches. It only supports Registered DDR PC1600/2100 memory, so your old DIMMs won't work. Your old power supply won't work either. The Thunder K7 needs an extra 8-pin power connector. It's not the same extra power connector that Intel Pentium 4 Xeon-based motherboards need either, so you must get a special power supply that currently only will work with this one board.
Some of the printed manuals have a misprint on page 13, in the section “CPU Front Side Bus Jumpers”, says Jeff Nguyen of ASL, Inc., one of several vendors using it. Check the PDF version on Tyan's web site for the correct settings.
If you don't want to get a special power supply, new motherboards coming out soon from Tyan and others won't require it. Typical next-generation boards will be regular ATX-sized, run off standard ATX power, use 90 degree DIMM slots instead of the S2462's angled slots, and have no onboard net, SCSI or video. They'll also be cheaper.
Because of the 90-degree DIMM slots and lack of onboard video, the small boards won't fit in 1U rackmount cases, but their smaller size will give you more options for tower cases.