Please don't mistake my engagement for dismay. I enjoy your analysis. >> SuperMicro sells a 2U machine with 4 full sized computers in it with 6 drives. >You

Please don't mistake my engagement for dismay. I enjoy your analysis. >> SuperMicro sells a 2U machine with 4 full sized computers in it with 6 drives. >You can put 12 cores in that In fact, the quad node contains 4 motherboards. Each motherboard supports 2 processors. So that's 8 processors in 2U, or 4 processors per U. Each E5-2600 processor could support 8 'real' cores, or 16 Amazon Virtual cores. 4 * 16 = 64 Amazon cores in 1RU. I agree that our math won't be right, and I think you're in the ballpark. But, the densities can be 'hella' higher than one things with modern gear. It's only 70W for the 8 core processor at 1.8ghz, 135W for the 2.9Ghz version, so if we do 4 processors per rack unit, that's "only" 540W per rack unit. 60 Rack units is 32KW/RU - which is a lot but not impossible. I'm gently simplifying by assuming 0 watts for the rest of the chassis, which is approximately reasonable if you're building a CPU farm.