yes, but it is expensive. You can look on ebay and find the cards for the M17X. Just make sure you get the card, heatsink and fan for the card (some come with it all some do not) I did this on my M17X17, switch from the 260M to 5870.

I already have an nVidia card, I was just wondering if Id be able to take out my ATI card and put this one in. I have the heatsink and everything for it also. Would I just need to install the drivers?

Dude, I got a GTX580M....nothing but problems on my M17xR3. The official Alienware driver for the card is back from July. Nvidia has released several updates but there is no support from Alienware. Be warned.

My M17x is an R1 still. So what ever driver is available, I'm sure it would work.

You will need to unistall the drivers for your current card, and I recommend downloading and running Driver sweeper. Then power off your laptop and remove card. Then install the new card. Then power on the laptop and installl the drivers for the new card.