I have a Dell Precision M6600 with an AMD FirePro M6100 2GB. I've found a company claiming to sell GTX 970M/980M MXM 3.0b GPU upgrades for this laptop (including thermal pads and bracket, natch.) However, on some forums I've seen claims that the best upgrade available for this laptop (due to BIOS compatibility issues) would be a GTX 680M. Does anyone here know whether or not a 9xx class Nvidia GPU would even POST?

Note: I'm not a professional user, so I'm not really interested in Quadros or FirePros, unless they're at a deep discount. The FirePro I have performs very nicely in games, but the price premium on a new CAD GPU is on the exorbitant side.