after testing with a watt tester and amps several script algo including Folding@home, this what i find out:

Based on 6 x GPU cards (R9 280x) on one motherboard:
Primecoin (XPM algo) - Miner: Claymore - Watts: 1870 watts - Ampers: 6.10 amps
Folding@home algo    - Miner: F@H       - Watts: 1243 watts - Ampers: 5.4 - 6.1
X11 Scrypt algo        - Miner: SGMINER - Watts: 1010 watts - Ampers: 4.5 - 5.5

Remember, this numbers are based on 6 x GPU cards:

Test equipment
4 x R9 280x Sapphire TOXIC
2 x R9 280x MSI Gamer OC
2 x PSU: 1)1200 watts PSU & 2) 1000 watts PSU

I hope this info will be usefull to others