http://pcpartpicker.com/ is hands down the best site for designing your build. http://www.anandtech.com/bench/ Anandtech's benchmarks, while incomplete, are great to compare whichever GPUs/CPUs you'd like (that they've benched). http://pcpartpicker.com/p/Nzj6wP Here is a FO4 build I made for someone else, same $500 budget. You could change the video card to this reference R9 290, but the cooler has its spectularly terrible reputation for a good reason. It's hot, noisy and possibly ugly. The card is a good amount stronger than the 280x though. You could also remove the cooler and put a better one on, which is not too difficult from what I've heard. A couple other sites to check out are: https://www.reddit.com/r/buildapcsales A bunch of people posting cool sales. Check this out before you make a purchase. http://gpushack.com/ A recent startup from a redditor. He resells refurbished GPUs. I have not dealt with him but I've seen nothing but praise for his work. Don't take my word for it though. Finally, https://www.reddit.com/r/buildapc is a nice place to post a build you're considering to have it looked over.