Graphics Card Testing

Hey all,

I have a GTX 580m & a 6870m that are faulty and I need to check if its a total failure on both the cards or if they have had they're bios' flashed badly and just need a simple re-flash.

So is it possible to leave a working graphics card in the master slot of my m17x R2 and then place the faulty one in the secondary slot to see if they are detected at all?

I have obviously tried them both in the master slot but all that happens is the fan spins at full speed and no post.

Reason I'm asking is that I don't want to screw up my good card in the process! (6990m)