Alienware M18x R2 - SLI Question

Which card runs normal windows operation?: The primary or secondary GPU. When no game is running... Also specificly which is the primary GPU heatsink. ( I'm trying to figure this out because one of the GTX 675m in the system I'm parting out is bad and I know the other is good.. but not sure which one it is other then being the card that isnt used for basic windows operation. - Thanks

If I need to clarify anything let me know.

 

Left card (looking from front) is primary. Both cards runs at windows level and divides work to both so system is cooler than with one gpu. Laptop won't start if primary GPU is damaged even if secondary is working. If secondary is damaged laptop will start and use only primary card.

I have two 880M in M18xR1 feel free to ask more questions if you want.

 

So if in fact the primary GPU was bad ( giving windows a blue screen on boot ) then there would be no way that the secondary card would actually be booting to windows. Now since the issue the Alienware M18x R2 I parted out was having was not that. ( windows booted fine ) but when a graphics intensive app opened or even "polled" the gpu to go into 2nd power state there would be a blue screen. Would this mean that both GPU's were bad or the primary is in fact good. Or the only way to truly know is to test it .. Which I only have my Alienware 17 so it is going to be a pain haha.

 

I just had to figure this out recently when one of my 980s went bad. I first took both cards out to make sure it was not software problem. It booted fine with internal integrated GPU. Then placed one card in on the left side (primary side). Played about half hour worth of gaming, the card worked fine. Placed second card in primary slot, immediately got artifacts on screen, and eventually screen went black and pc shut off. When I tried to turn pc back on I got black screen. Eureka, I found bad card. The only thing I find odd with your situation, is your pc giving you BSOD on boot. Are you sure its a bad card and not some type of software problem? I did not get BSOD with my bad card, then again everybody is different. Good Luck

 

Figured it out and tested both cards in my Alienware 17 (I'm parting my M18x R2 out) the card I thought was bad was infact bad it was the primary ( it was bsoding and stopped showing up in device manager..) but other one was fine. What is weird however is the one that is bad would play for 15min but randomly bsod as well as stop showing up in the computer.

 

It can be partially damaged. Run the diagnostic test on primary damaged card in BIOS and check if GPU memory is damaged, if yes send it to resolding service. One of my HD6990M was repaired this way and sold on ebay.