MauveCloud :
Yeah, it should fit. I'd advise getting a new power supply if you're overclocking your cpu (I'm guessing you might be because it looks like you have a tower cpu cooler in that picture), though. Recommended psu for a gtx 680 is 38 amps on the +12V rail and 550W total (ref http://forum-en.msi.com/faq/article/power-requirements-for-graphics-cards), but that's before considering overclocking. Your Seasonic SS-520GM psu will give you 40 amps on the +12V rails.
uhhh, I just received this power supply with warranty but I dont know about overclocking....
this is my setup:
Case: Cooler Master Midi Tower Gladiator 600 ATX No PSU (zwart)
CPU: Intel Core i7 870 2.93GHz 2.5GT/s 8MB Box
RAM: Kingston 2x2GB DDR3 PC10666 CL9.0
Motherboard: MSI P55A-GD65 iP55, SATA600 RAID, USB3.0, GLAN
Hdd: Samsung 1TB SATA300 32MB, HD103SJ
DVD: Samsung DVD-/+/RAM SH-S223C 22x/22x/12x SATA Bulk (zwart)
Cpu cooler: Scythe Processor Koeler Mugen 2 Rev. B AMD & Intel
Gpu: XFX Videokaart PCI-e Radeon HD6850 1GB 2xDVI/HDMI/DP
Power supply: Seasonic M12II 520W
My upgrade:
Msi r7970 OC
SSd samsung 840 evo 120gb
extra Hdd barracuda 2TB
and 4 gb RAM (2x2GB cl9 1333 kingston)
not planning for overclocking, just an upgrade for the next generation games... and ssd for speed
I have been told that this power supply should be sufficient....