PC will not boot with 2 sticks of ram (think i've tried everything)

[lukehiggins908]

I have a set of 2 new 8gb corsair vengence DDR3 Sticks (cmz16gx3m2a1600c10r) from a recent RMA with corsair (replacing the excat same sticks i brough back in june) now if i mount them both my pc will not boot to bios but with one stick it boots as normal. i have tried each RAM stick in each DIMM slot and all works if there is only one stick. when i first installed the sticks all was ok then i got a random BSOD for system thread exception not handled and now this happens - i am at my wits end - id like to know how i can better pin point the issue before i shell out money for new parts.

my mobo is MSI B85-G43 (not the gaming one)
cpu is intel i5 (i dont have exact info to hand)
nvidia gtz 970
600w PSU

i have tried what has been suggested in various other threads ajusted DRAM voltage in BIOS - manually set it to DDR3 1600 - there are no BIOS updates (i am on 3.9)

 

[vapour]

did you put 2 sticks in ram slot 2 and 4?

assume from left to right we see: CPU, ram slot 1, ram slot 2,...3,...4

 

[lukehiggins908]

did you put 2 sticks in ram slot 2 and 4?

assume from left to right we see: CPU, ram slot 1, ram slot 2,...3,...4

Yep
Still no luck

Could it be a PSU issue? It will boot with both sticks in but with my 970 taken out.

 

[vapour]

Did you try let ram run by default? Instead of manual setting XMP.

 

[lukehiggins908]

yes i have (i used default settings from the beginging) i have never really played with BIOS settings before, only when i looked at potential solutions by google searching

 

[lukehiggins908]

tried with a 750w psu jsut to test and still the same happens