[Thermodyne]

Yes, there is some research into stacking chips on die. But with the heat issue continuing to plague the 90 nanometer chips, stacking is a ways off yet. Early 90nano chips are reported to leak more than 50% of the power that they consume. Tandem chips on die is closer, but that is a side by side arrangement. With x86, quad chips on board is about the performance/price limit. But for some applications, 8 chip systems serve well. Another arrangement is blades, where “systems on a card” are stacked in a high speed buss arrangement. The larges one of these that I have personally seen had 24 blades/CPU’s.

For folding or crunching seti, stacks are some times used. They are striped down systems that are served by a complete system w/hard drive. The rest of the stack is just main Boards, CPU and ram with a NIC. By eliminating the additional hard drives and cases, a low cost high performance system can be built. If all goes well and I can get a grip on Linux, I’ll have a 17.4GHz stack running by new years. The cost will be about $83 a GHz. Output should be 8 times what I get from my FX51 which cost way more than the whole stack will.