Keep or trade PSU's

So currently I have an OCZ Fatal1ty 750W PSU in my PC right now and I was given a BNIB XFX XTR 650W PSU.



Should I keep the one I currently have in or should I go ahead and stick the other one in? I like the fact that the XFX is fully modular instead of semi modular but to be honest, PSU knowledge isn't my strong point so any help would be great.



Current setup is:



i5 2500k at stock

MSI 970 100ME

Samsung Evo 250 GB

1TB WD Blue

Sound Card (Forgot which make and model but think its a creative)

HAF 922 (Two LED 200 MM fan) (One 200 MM Fan) (120 MM Exhaust Fan)

ZALMAN CNPS9700 LED CPU Cooler

Keep or trade PSU's