GA-Z77-D3H Boot loops / System stability issues / Random shutdowns.

[thed.]

Firstly I'd like to say hello to everybody, this is my first time on TweakTown Forums.

I have recently assembled a rig and there's some major problems with it's, I'd like to point out that it's not my first build, I know my way around when it comes to building pc's and doing some basic troubleshooting however, what I am about to explain has never happened to me before.

My main issue is the fact that my PC has been shutting down during gaming sessions and then going into boot loops (turns itself on, all lights come on, fans spin and then it shuts down and repeats the process). Sometimes it was happening after 20 minutes of heavy PC usage, sometimes after 1 minute.

Another issue I am having is lack of system stability, insanely long application / folder open times (Takes about 10 seconds to open my computer). Applications such as Photoshop are stuck on "not responding" status for about 30-40 seconds and then they proceed to load everything in 3 seconds.

Last issue is occuring whenever I decide to put my ram stick into other slot on my motherboard, after doing so, my PC goes into boot loops and shows popup window saying that "Bios has been corrupted, please wait for the recovery".

I thought at first that the issue could be related to low amounts of ram (I lacked appropriate funds back then so I've decided to save up on ram), however the ram has passed memtest.

Things I have tried:

BIOS flash to F18 version
Disabling C3/C6 States
setting BLCK to 100.1 MHz

I'd also like to point out that whenever I try to work in Sony Vegas my preview is really laggy but I guess that's due to low amounts of ram.

I would appreciate any suggestion on what is possibly causing the problem.
My plan is to order a new board and 8GB of RAM, because I think those two things are the main cause behind those problems, correct me if I'm wrong.

P.S. I am not a native speaker, sorry about grammar mistakes.

@EDIT

I have just ran Prime 95 test for 15 mins, my computer has shut down after that, does it mean my CPU is faulty? I have ran In-place large FFT test.

[wazza300]

have you set cpu voltage response to fast in the bios?

using x.m.p for your memory if it supports it? it could be down to you running a sandybridge cpu on a z77 board,it might not be supported aswell as an ivybridge i dont know,it could be other things

if its failing prime95 then it not stable as in a voltage/setting somewhere

[thed.]

Thanks for the response,
I have not messed with voltages or any similar settings in BIOS, everything is on auto, I will try enabling XMP and setting Vcore voltage reponse to fast and see what happens.

[stasio]

Just info,
is well known OCZ PSU did not play well with GB boards.

[thed.]

I have set vcore voltage to fast and unfortunately wasn't able to set XMP in options. Issue still persists. I am purchasing the ASrock Z75 Pro3 and additional ram to see if it will fix the issue, will report tomorrow when I get and install the components.