I use 850 watters on 780 builds to allow for adding a second card in SLI...... 600 watts works for a single card installation but there's no sense in getting anything less than 620-650 watts as price differences are tiny. However, twin 980s could prolly get by on a 750 watter since each card draws about 90 watts less.
http://www.geforce.com/hardware/desktop-gpus/geforce-gt...
Quote:
980 Thermal and Power Specs:
98 C = Maximum GPU Tempurature (in C)
165 W = Graphics Card Power (W)
500 W = Minimum System Power Requirement (W)
2x 6-pins = Supplementary Power Connectors
500 + 165 = 665 watts for SLI
http://www.geforce.com/hardware/desktop-gpus/geforce-gt...
Quote:
970 Thermal and Power Specs:
98 C = Maximum GPU Temperature (in C)
145 W = Graphics Card Power (W)
500 W = Minimum System Power Requirement (W)
2x 6-pins = Supplementary Power Connectors
500 + 145 = 645 watts for SLI
I'd use a 750 or 850 w/ overclocking
http://www.geforce.com/hardware/desktop-gpus/geforce-gt...
Quote:
780 Thermal and Power Specs:
95 CMaximum GPU Temperature (in C)
250 WGraphics Card Power (W)
600 WMinimum Recommended System Power (W)
One 8-pin and one 6-pinSupplementary Power Connectors
600 + 250 = 850 and that's enough .... I have two OC'd 26% and the system pulls 745 watts from the wall (670 watt output)
$50 750 watt PSU
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
$85 850 watt PSU
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
The B2 isn't quite the unit the G2 and P2 are but at those prices hard to turn down.
tho as with the 780 question (why not a 980 ?) ... if you upgrading MoBo / CPU (wasn't clear if that's what ya had or that's what ya gettin) why not a 4690k or 4790k w/ Z97 ? I'm guessing that ya keeping the old MoBo / CPU but if you upgrading those consider that too.