Hello Kato,

I have such sets, 3x7950 and 4x7950 (gigabyte cards) with 'Gigabyte GA-990FXA-UD3 AM3' mainboard and on Chieftec bps-1200c power supply it's like 850-900W on 3 cards and 1000-1050W on 4 cards.

Good luck,
Dave