Im going to have to say that that PSU is not something I would advise you power two graphics cards with. In fact I wouldnt advise using it at all.
PSU's are arguably the most undervalued component of a PC. If you buy a cheap one, chances are your not getting anywhere near the power output that it says it can do. Also, the materials and manufacturing process used to build it will most likely be as cheap as it is.
A cheap and poorly made PSU can kill an entire system if it fails. Just looking at some the reviews for that PSU:
- "Pretty much worst thing I've ever spent money on. Cost $60, and within seconds took out $400 dollars worth of equipment."
- "I hate giving such a low review but I'm being honest. The price is tempting I know but I got two DOA's back to back so don't waist your time."
- "Fan was broke when i opened it, did not support high end cards and cheaply made"
If I were you, Id be staying well clear of that PSU and brand in general.
Some good brands to choose are: Antec, Seasonic, Corsair and XFX