I’d recommend you upgrade to a 330w PSU, and the 870M is a problem you don’t want. try and use the 9xxM series GPUs and I’d recommend talking to the professional about this stuff: [NAME] . and the max cpu is a 4940MX.
Hello, I have a 2014 Alienware 17 R1 with the i7-4700qm  cpu (which I am deciding on a good cpu upgrade at the moment, and 32gb of ram, and originally had the gtx 765m gpu, been upgraded to the 780m gpu.. I have a 240w psu for it, and was wondering if it could handle the gtx 870m, or if I would need an unlocked bios for it. and if so.. Dell branded or Clevo.. I hear they are pretty much the same. Fortunately my gpu cooler is the style with the three heat pipes and it manages to stay cool with the gtx 780m. I don’t do intensive gaming on it so I’m not worried that (1) it’s an older system, or (2) it’s an older gpu. I can promise you i paid less for the laptop than what the gpu will probably cost (let’s thank storage unit auctions for that)
2014 Alienware 17 R1 GPU compatibility.