hi guys i have a core 2 quad 2.66ghz nvedia i790 motherboard 4gb ram & 650watt coolermaster powersupply.is it possiable for me to add 2 radeon 4850 x2 croossfire.I am a bit confussed about the power. as per the coolermaster psu calculator i need 850 but some say amps matter not watt. what to do ????
Considering each 4850x2 consuming 250W,two of them would need 500W..Since around 95% power is drawn from 12v rails you would need a power supply which can provide at least 40amps on the 12v rails...Further your processor consumes around 200w under full load...current required on 12v rail by cpu is 16Amps..Therefore the net current drawn by 2 gpu+1 Cpu on 12v rails is 56amps..Hence you need a psu which can provide at least 60Amps on 12v rails