Wow, with my 2 GPU cards crunching away happily my power meter is showing a usage of 390W total for my quady while crunching SETI as well. Never seen it that high before. Sweet!

Well my powermeter shows 510W if I crunsh MW with 2 ATI GPUs and crunsh abc@home with the 2 Quadcore Opterons ...

Not mine but 1.65 kWh on 2x Xeon 3.6GHz + 2x4870x2

1,6kWh is too much for 2 CPUs and 2x2 GPUs:
the 4870x2 use up to 300W - 2x = 600W
the CPUs dont use more than 150W - 2x = 300W
+ HDDs etc = 100W

600W+300W+100W= 1000W -> 1,0kWh (1,3kWh if its a "bad" PSU !)

1,6kWh is too much for 2 CPUs and 2x2 GPUs:
the 4870x2 use up to 300W - 2x = 600W
the CPUs dont use more than 150W - 2x = 300W
+ HDDs etc = 100W

600W+300W+100W= 1000W -> 1,0kWh (1,3kWh if its a "bad" PSU !)

Unless he's using SAS drives, or including other stuff like a CRT monitor in that quote. Or if they are overclocked. My guess is that it's all connected to one socket and he's referring to that socket. There isn't a 1650W PSU on the market - he'd have to use 2x800W or similar.

By my reckoning:

Name - Price / £ - Power / W - 6-pin - 8-pin - Other
3850 - £67 - 90W - 6(1) - - Single Slot
3850x2 - £110 - 180W - 6(1) - 8(1)	
3870 - £75 - 110W - 6(1)		
3870x2 - £150 - 230W - 6(1) - 8(1)	
4770 - £80 - 80W - 6(1)		
4830 - £75 - 110W - 6(1)		
4850 - £85 - 130W - 6(1)		
4850x2 - £150 - 260W - 6(1) - 8(1)	
4870 - £115 - 150W - 6(2)		
4870x2 - £240 - 300W - 6(1) - 8(1)	
4890 - £151 - 190W - 6(2)		

Someone correct me if they disagree. On a side note, I'd recommend 1.2x the total power requirement of your system in a PSU

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