new Computer BSOD and freezes

[acegaming90]

hello

i built a new pc like a month ago and been having issues with it, to start off with is i had few BSOD,i did a full reinstall of windows but nothing changed ( actually it got worse ),
sometimes my PC would just freeze and no response so have to power it down manually,
after the last install i also get this warning pop up on chrome saying Rats! WebGL hit a snag...
theres also when doing GPU benchmark it get flicking in screen , small ones but happen when pc is underload .
and my Monitor dont seem to detect my DHMI cables, it detects only DVI or VGA with DVI adopter , with VGA + adopter i see flicking when doing other things too.


so asked few people , few say its my GPU or Ram , few say it could be my PSU but as i just bought this system and not good with pc i need some help narrowing down this issue if anyone would be kind enough to help me please.


heres my system

i5-4670k
XFX 550w
Sapphire radeon 7950 Vapor X
z87-A
Avexir Core Series blue LED, DDR3-1600
Windows 8 pro 64bit
samsung 840 series 120gb
WD blue 1tb

 

[acegaming90]

ran memtest86+ for atleast 7 passes individual stick and 7 together , seemed fine.

also ran prime95 today and some weird thing happened , i let it run but m y computer went to sleep mode coz i wasnt around to keep it up, and when i tried to wake it up , NO signal found , PC was running but just no signal on monitor.so had to power it down manually and when i boot it up again it was detecting screen.

also last night my screen just went black when gaming and had to yet again power down with switch.

also if it helps for some reason my HDMI cable (tried 2 different) wont work , monitor just dont detect pc , so have to use DVI cables.