Please help me upgrade my graphics cards

Ok, I never thought I would be having as much trouble as I have upgrading graphics cards. Lets start with the M18x R2 I have.

M18x R2: Originally came with 7970M Xfire, replaced with 8970M Xfire, then changed to 780M SLI. The 8970M worked fine out of the box no modding required, but the 780M caused weird lines on the screen. They work 100% fine in the Alienware 18 they were pulled from, but no matter what, they caused weird lines on the LCD if I used them in the M18x R2. What the heck gives? I'm at my wits end here.....

M18x R1: Came with 6990M Xfire that died, replaced with a single R9 M290X with a Dell vBIOS. The RAID screen shows up fine, then the BIOS boot screen gets all corrupted graphics, then when it loads to windows...the graphics are fine again? Wtf? I tried to blind navigate my way into the ePSA system where I tested the video card, and it passed too as well as the LCD when I tested it. I tried a Clevo vBIOS and i got 8 beeps with that. I don't know if I should try a single 780M, I feel like there would be problems again there too...
EDIT: M18x R1 is resolved...it was a weird vBIOS issue. I had to flash the R9 M290X crossfire version of the vBIOS to get it to work properly.

@Mr.Fox if you're reading, I could use some guidance here.


Some help would be much appreciated fellas. Get these beasts roaring again!

 

I sold my R1 and it only cost me 300 bucks to upgrade to a a18 with 780 sli. Other than a ssd drive it have left it alone and dont overclock and its been working awesome.

 

Thanks, but I have absolutely no love for the Alienware 18 and would much rather keep my M18x R1 and R2.

 

I lost my love for the r1 when i had 3 6990 video card failures in less than 1 year. The machine felt like a ticking time bomb to me. I was always glad to see it still running every morning it was that bad. Good luck with the r1

 

So if anybody has any ideas or clues as to why this his happening, I'd love to know the fix. Are there any special instructions for installing a single 780M in the M18x R1?

 

@Raidriar The main thing that I can think of with your R2 is that some left over parts of the AMD drivers are messing with the 780m. Does the system boot with the 780m? Do you get lines with integrated grahics? I'd be cleaning all drivers with DDU (amd and nvidia) even if you have already done so, cmos clear/power drain, re-seating the gpus, could also try a fresh windows installation as a last/final measure. Otherwise I have no idea.

 

The problems occur before Windows, in the BIOS/POST process. No problems with AMD cards or Intel HD, but the 780M causes weird lines. and I can't see anything on the screen.