make sure you have all the mb bios update for your mb.
P8Z77-V BIOS 1805
is the last bios update and have updates for cpu and ram code.
in the bios make sure under ai tuner the dram speed you have it set to xmp profile so your ram running at the max speed.
check to see if you installed the LucidLogix Virtu MVP Software. it causes issues because it tries to bond the intel ipgpu with a gpu for faster frames in games..the software tech is to buggy it should never have been places/sold. check that your monitor is on the gpu and not on the onboard video card. make sure you installed the newest intel chipset drivers and the june update for direct-x. also for the realtek sound card the newest driver is 2.7 on there web page. you also want to install msi afterburner and set a fan profile. there is a bug glitch with nvidia video drivers and when the gpu fan spins up to cool the gpu down. if the fan does not ramp up quickly with the heat of the game load then your gaming rig going to lock up or drop to the desktop.
I would check your ps 12v leg see if there one or two and it amps and voltage rating. see if with your high end gpu card your close to the 12v rail max output. you may be pulling more power then the ps can give you. i would also download hardware monitor watch your cpu and gpu temps..make sure there fine. when you go to bed..boot off of a hirem boot cd or usb stick and run memtest overnight. make sure your ram is fine.