I was wondering if this PSU is any good, I'll be using it with my HD7970 and my I7 950, my old 600w EVGA PSU died on me so I was wondering if this would do the same, since I heard the 7970 is quite a power hungry card.
And for Tier one PSU, i suggest either Seasonic X-650, Platinum 660 or PRIME 650,
pcpp: http://pcpartpicker.com/products/compare/Fgwqqs,CfXfrH,nn648d/
Note: Seasonic PRIME 650 is the best 650W PSU money can buy at current date. (My Skylake build is powered by PRIME 650, full specs in my sig.)
PSU review...
I don't know from where you heard that Corsair CXM PSUs are made by Seasonic. But i can say for sure that the OEM for Corsair CXM series PSUs is Channel Well Technology and not Seasonic.
The only PSU series that is made by Seasonic for Corsair is their AX series. Most Corsair PSUs are made by Channel Well Technology, while they also have PSU lineups from Flextronics (AXi series), Great Wall (CS series) and Chicony (RM750; the rest of RM series is made by CWT).
If you have the newer model with black lettering on it's side then your CX650M is mediocre quality (Tier three) PSU. But if you have the older model with green and white lettering, then it's low quality (Tier for) PSU.