Bsod And Rsod. Plz Help!!!

Hi Guys

I have been experiencing problems with my PC. Earlier when I had installed win 7, I used to get bsod while gaming. BSOD error 0x124. After installing windows 8.1 I get RSOD(Red screen of death) while playing high demanding games.

My pc specs:-
Amd Phenom II X6 1090t (Processor)
ASUS M5A78lm-usb3(Motherboard). (New)
4gb Kingston 1333Mhz (Ram)
Seagate 500gb SATA
Sapphire HD 6850 1gb (Graphics card)
Corsair VS 650 (PSU) (Almost 2 years old)

Allthe rest system parts are almost 5 years( will complete 5 this November)

I tried testing memtest86+ with 8-12 passes. No errors. Replaced HDD with other 500gb HDD. Replaced Ram with my friend’s RAM. Still getting RSOD on windows 8.1.

Games on which I experienced RSOD

  1. Bf3
  2. Bf4
  3. Assassins creed Rogue
  4. WWE 2k15

Games on which I haven’t experienced RSOD yet

1.Pro Evolution Soccer 16

Plz guys I need help!!!

Video card drivers up to date?