Coolermaster eXtreme Power Plus 650W, how is it for the 580?
and another thing
would my intel i5 650 bottleneck the gtx 580?
Cooler.master makes some OK supplies and some horrible ones. The extreme power plus series belongs in the horrible section. Your current PSU can deliver more power than that coolermaster.
the coolermaster will not even get close to what its rated. see this review for the 600W model