Planning videocard SLI : 700w PSU enough?

[Sokonomi]

Hello all,

I am planning on adding an extra videocard to my setup, but im a little worried my old 700w PSU wont be able to chug it.

This is my system:

Spoiler

CPU: Intel Core i7-920 2.66Ghz Quad-Core Processor ($305.97 @ Amazon)
CPU Cooler: Antec KUHLER H2O 920 110.0 CFM Liquid CPU Cooler
Motherboard: Gigabyte GA-X58A-UD5 ATX LGA1366 Motherboard
Memory: Corsair XMS3 12GB (6 x 2GB) DDR3-1600 Memory
Storage: Western Digital Caviar Black 1TB 3.5" 7200RPM Internal Hard Drive ($80.98 @ OutletPC)
Storage: Western Digital Caviar Black 1TB 3.5" 7200RPM Internal Hard Drive ($80.98 @ OutletPC)
Storage: Samsung Spinpoint F3R 1TB 3.5" 7200RPM Internal Hard Drive
Video Card: Zotac GeForce GTX 670 2GB Video Card
Case: Fractal Design Define XL R2 (Titanium Grey) ATX Full Tower Case ($123.99 @ SuperBiiz)
Power Supply: Cooler Master Silent Pro M 700W 80+ Bronze Certified Fully-Modular ATX Power Supply
Case Fan: Cooler Master R4-MFJR-07FK-R1 110.0 CFM 200mm Fan ($12.26 @ Newegg)
Case Fan: Zalman F3 (SF) 120mm Fan ($11.99 @ Newegg)
Case Fan: Zalman F3 (SF) 120mm Fan ($11.99 @ Newegg)

Partpicker claims my system currently pulls about 475w of power, and the card I plan on adding is listed for about 170w peak. That would make for a grand total of 645w, leaving a 55w (8%) overhead. I also have my CPU overclocked to 3.44GHz, so that might add some additional drain as well..

Would adding an extra card and possibly one more 120mm fan pose a problem?

 

[MarkW]

Each of those cards uses roughly 170 watts. So when you go with SLI, the two will use up to 340 watts. And that leaves 360 watts for the rest of the system, which almost never goes over 200 watts. So you should be fine.

 

[Sokonomi]

Even with the overclocked i7-920?
Says here that thing chugs a heaping 247w in OC mode;
http://www.tomshardware.com/reviews/overclock-core-i7,2268-10.html
That's a whole 117w more than partpicker is pegging it for. 🙁