Dell xps 8500 gtx 900 series cards compatibility

It doesn't need to be said that the currently distributed dell xps 8700 are having issues, apparently relating to the bios, regarding the upgrade of their graphics card to a 900 series.

I'm currently undecided whether I can be sure that the 970/980 is going to work in the xps 8500 after reading posts by multiple people about their card working in the machine with the latest A12 bios. Due to this, I'd like to just be aware if anyone else has tried to upgrade their 8500 with a 900 series graphics card, and if it worked or not, before I take the plunge into buying it, and testing it myself.

Thanks :)