Where does a 650W PSU fall short on a gaming rig

[iocaine1]

if the build is

i5 3750K
Gigabyte Z77-UD5 (motherboard)
8gb Kingston HyperX
Single Nvidia GTX 670
Dual monitor setup (1 for gaming)
webcam/keyboard/mouse/phone charging...
Likely air cooled (yet to decide on cooling unit)

I dont believe there should be any problem with a 650W 80+gold psu.
for reference im looking at the: CORSAIR Professional Series Gold AX650 650W


So many gaming rigs use the 750W. So i have 2 questions then

1. Where does a 650W fall short?
- I dont plan on overclocking past 4.0GHz
2. Why do so many people seem to opt for a 750W?
- (by far the most common i see for my general price range)

 

[DJDeCiBeL]

You'll be perfect with that Corsair PSU (even slight overkill). 750W+ (even though I have a 750W PSU myself, with only a single card), is only needed for SLI/Crossfire.

The recommended minimum for a 670 is 500W, but it's good to have some headroom.

 

[iocaine1]

In the future if i decided to go SLI though, it would be recommended to upgrade the PSU though would assume.

 

[DJDeCiBeL]

In the future if i decided to go SLI though, it would be recommended to upgrade the PSU though would assume.

Probably, yeah. Even as good as that Corsair is, it would be on the edge of cutting it for two 670's in SLI (though I'm sure some will say it would be fine).

 

[amuffin]

A better option would be the Seasonic X Series X650:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151088

It's essentially an AX650 with better fans, and sensors 😉

Review:
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=169
9.5 rating!

 

[iocaine1]

Best answer selected by Iocaine1.