GTX 980 on Alienware X51 ?

http://www.alienowners.com/showthread.php/6088-Nvida-GTX-970-980-are-making-Alienware-X51-the-BEST-PC-IN-THE-WORLD-(LOL)?highlight=GeForce

To summarize that link for you, the 970 works on the alienware x51 perfectly fine.. you can even use over clock version, as for the 980 as long as you buy the stock version you should be fine. any over clock and it will burnout

Now these new gpus are 1 inch longer than the 760 Ti so it gets a snug fit and you might have to play around to get it in and also theres a fan that gets in the way, you would either have to remove this 20mm fan or swap it for a 10mm fan.

This is good news! this makes the x51 good to GREAT, max settings, ultra 1080p , maybe 4k. its crazy how the stock 980 uses less power than the 760ti.

I put a PNY gtx 980 (reference design) in my alienware x51 r2. Removed disc drive and moved the one fan over to fit it in but works like a dream. Heat is about the same as the blower design is the same as the titan and is fantasic. Makes more noise but its worth the payoff imo.