LOL it's not even close to a single 20A breaker
Breaker 1 runs: 3930k, X5670, X5650, AMD X4 955 #1, 3770k #1, 2600k, 3x i5-2400, 4 laptops, the FX8350, and my "desk" stuff (box fan, 2 monitors, router, switches, speakers)
Breaker 2 runs: AMD 4P (32c), i5, AMD X4 955, X5672 DP, i-920 #1, i3-3220, AMD 2P (24c)
Breaker 3 runs: 4x i5, MegaTablet, i7-860, i7-4770, i7-920 #2, 2 Dell T5500s (DP E5620s), IBM X3500 M2 (X5550), DP X5690
So, I have things spread out quite nicely, because otherwise there's no way in hell it would all run
I don't have exact numbers, which is why I've refrained so far. I'm just basing it off of what HWMonitor reports for the CPU, an estimated power for the motherboard/HDD, and that HP equips them with 80+ Bronze PSUs.