How much power is really needed?

[Konceptz804]

Time to build a new rig, but I'm at a lost for how much power is really needed. When I built my last rig kilowatt PSUs were the rave, but is all that power still needed? Machine will be overclocked

I7 2600K
MSI P67A-GD65 (B3)
8GB DDR3 1600
At least 3 Sata hard drives
2 sata Opticals
GTX 560ish video card

 

[DarthV]

I'm still using a corsair hx520 with my 2500k build in my sig without any issues. Then again corsair doesn't make a modular ~500w ps anymore and with weekly deals from an unmentionable canadian e-tailer, if I were to upgrade I'd probably get an hx750 (or ax750). Couple weeks ago, I could have bought an ax750 for $10 more than a hx650

 

[tonytnnt]

You'll have a moderate 12V rail draw with the GTX560 and all those drives. Overclocking will add additional load to the PSU. If you get a good 750W or above PSU you'll have no problems. I'm using data from this review for GTX 560 power consumption, and this site for a peak current (i.e. startup current) for hard drives. This leads me to believe that you'll have about 300W max draw from your graphics cards and 3 hard drives. While these peaks are unlikely to be concurrent, for the money I think it would be better to be safe with a 750W PSU than probably okay with a 650W.

Here are some good 750W PSUs:
$110 (before $15 MIR) - CORSAIR CMPSU-750TX 750W ATX12V v2.2 SLI Certified CrossFire Ready 80 PLUS Certified Active PFC Compatible with Core i7
$120 (before $20 MIR) - XFX Core Edition PRO750W (P1-750S-CAB9) 750W ATX12V v2.2 & ESP12V v2.91 SLI Certified CrossFire Ready 80 PLUS BRONZE Certified Active PFC
$130 (before $20 MIR) - XFX Black Edition P1-750B-CAG9 750W ATX12V v2.2 / ESP12V v2.91 SLI Ready CrossFire Ready 80 PLUS SILVER Certified Modular Active PFC
$150 - Sparkle Computer Corp GOLD CLASS SCC-750AF 750W ATX12V / EPS12V 80 PLUS GOLD Certified Modular Active, 0.99PF Typical PFC
$160 - SeaSonic X750 Gold 750W ATX12V V2.3/EPS 12V V2.91 SLI Ready 80 PLUS GOLD Certified Modular Active PFC

On the more expensive ones, you're mostly paying for modular cables and a more efficient power supply (80+ Gold being the most efficient.) For my money, I'd probably get the $130 XFX Black Edition because it's semi-modular and Silver Certified.