A few nights ago I went to play Overwatch as I had been doing previously that day and I was suffering from huge fps drops (down to around 10fps) and all of my sound would start stuttering. Once the game was closed the problems would persist throughout windows causing my mouse to stutter, these problems wouldn't be solved until I restart my PC. I tried playing Evolve and was greeted to the same issue. I've tried reinstalling drivers for my GPU and realtek integrated sound, disabling Nvidia sound drivers, turning off the integrated sound within the bios, fresh install of Windows 10 and Windows 7 (Installing only drivers and overwatch). Last night I tried running the game off of my IGPU and it ran flawlessly. Both GPU and CPU temps are hovering around 65-70C under load.
Specs:
Intel i5 3570k @ stock
Nvidia GTX 660Ti
Asus P8Z77-i deluxe
8GB Ram
Samsung 840 Evo 240GB
1TB Hitachi HDD
Both OS were 64 bit
Corsair CX 600w PSU
At this point I'm assuming its a hardware failure, potentially the GPU.