Hi there, for my new pc build I'll be getting a i5-3570k with a COOLER MASTER Hyper 212 Plus , ASRock Z77 Extreme4 and a SAPPHIRE Radeon HD 7870. I'd like to overclock my cpu to about 4.2GHz.
Is the XFX 550w Core Edition enough for this??
You will be fine, just fine sir. If you have intents on the future of getting a higher end card you will be fine with a single card however with a sli setup of two higher end cards you may run into issues.
2x 7970 no
1x 7970 yes
1x 7870 yes (good to go dude)