Will I be able to add another graphics card?

[Tyg13]

Currently my system is of the following build:

Mobo: Asus M5A97
CPU: AMD Phenom II 965 x4
GFX: Sapphire AMD Radeon 6870 1GB 256-bit
PSU: Corsair CX600 600W
RAM: Corsair DDR3 4GB 1600mhz x2
Fans: 120mm x2 on the side, 1 on the back, slot open for 140mm in the front

Running it through Newegg's PSU calculator, I get my power requirements at slightly over 650W, which leaves me worried that I'll buy this second graphics card and be unable to run it with my set-up.

Assuming my PSU won't be able to put out the required wattage, what wattage would I need support a second graphics card? I'm not exactly in the know when it comes to models, so if anyone has any recommendations, they'd be greatly appreciated. I'd prefer not to spend more than 300 dollars in total (new card + psu).

thanks very much in advance.

 

[Pinhedd]

The Corsair CX600 is a pretty reasonable PSU. According to the datasheet it provides 480 watts on the 12 volt rail. A stock 6870 will draw about 150 max which leaves about 180 for your CPU and motherboard. That's not a lot and it's an extremely tight fit but it should deliver since it's a SeaSonic PSU

 

[Tyg13]

Best answer selected by Tyg13.