Look for a different psu since that one can't provide it's labelled power output.
Is it good enough for a 5770? sure but is it good enough for your system ? i doubt it.http://www.hardwaresecrets.com/article/Cooler-Master-eXtreme-Power-Plus-550-W-Power-Supply-Review/969/1
The OZC suggested in this review is an option i would consider and the ModXtreme line also features modular cables.
I have a 600w model and i'm satisfied with it's performance after 1yr of daily use.
Antec Neo and Corsair VX are others i would consider in your price range as well as Seasonic.