Hey Guys any help will be very much appreciated.

I recently built my PC 6 weeks ago. Everything was initially fine; no crashes, no memtest errors, no blue screens. Not until I upgraded my bios version to 0707(latest version that time). This is when I start getting blue screens, game crashes, random computer freezing that happens quite frequently while gaming. I did memtest86 multiple times, it all show errors when I seat a ram stick on either slot A1 or B1. However when both slot A1 and B1 is empty, my pc works perfectly fine - no errors on memtest, no crashes and no freezing. I have to downgrade my bios version to the first version which is 0403 - This is when everything start working perfectly fine again. I wouldn't mind using this BIOS version, however I have to utilize iGPU multi monitor setting(for rendering purposes) which is not available on this bios version. I tried updating my bios to the latest 0804 - the problem became worse, my computer wouldn't even boot up if using all ram slots. I tried all other available bios versions - same results: no boot up. One work around I found was to only use 2 ram sticks on slot A2 and B2 - however I want to fully utilize all my ram sticks for performance and aesthetic purposes.

To sum it up:
Bios version 0403 - everything works fine
Bios version 0707 - blue screens, freezing and game crashes when using ram slot A1 and B1
Bios version 0607 and 0804(latest) - no boot up when using ram slot A1 and B1

Mobo: ASUS ROG STRIX z490-A Gaming
RAM: Gskill Trident Z Royal Silver 8gb x 4 pcs 3600mhz