How to calculate amps?

[Biernot]

is this the correct way to calculate?
basically i want 2 cards in SLI which take about 400w, another 150w for the cpu is 550w
so 550/12V rail = 46A ?
so if my seasonic 660w platinum gives 55A on the 12v rail, i should be fine right?

 

[azathoth]

That is correct.

Wattage (W) is Amperage (A) x Voltage (V)

So it's simple algebra, dividing the 550 by 12 gives you the correct amperage of 46A, and with a 660w seasonic Platinum PSU, you should be fine. Just don't load both cards with Furmark, which can FAR surpass any load you will ever see the cards use.

 

[Gam3r01]

What two cards are you looking at?
But yes, your math is correct. W=AxV.

 

[Zerk2012]

1 Amp = 12 Watts
with a standard USA 120 Volt outlet.
And as above if you list your hardware we can give you a better answer because some people have no clue (not to insult you)
I would not run 400 watts of cards and 150 watts of CPU on a 660 Watt power supply it leaves you pushing the limit when you factor in the rest of the PC when stressed.

 

[Biernot]

thanks alot guys it's ok, the cards in sli + cpu should use about 450w, took another 100w for safety incase i'll want to overclock.