It works fine in full hd. I'm lucky because it seems that this configuration is enough powerfull for all games. I can use Pcars with full settings and AA DS6X or DS9X (with just a few lower settings), to give an idea. By the way, Windows 10 is great, i recommend to do the change and the upgrade is free until the end of this year for windows 8.1 users. If you don't have windows 8.1 you can buy a key for 17 euros on Ebay. It works, that's what i've done for this pc (message me if you want information about the Ebay dealer).
Let's check the final price. PSU ATX 550 watts 32,85 -------------> replaced with a 700 watts due to missing PCie connectors 95 euros (glup) AMD FX-8320 136 euros ASROCK 970M PRO3 80 euros Kingston 4Go DDR3 HyperX 2133 35 euros Sapphire Radeon R9 380 4Go 170 euros -----> could have used the R9 285X 3Go for 160 euros (same performance) Bitfenix Prodigy M 82 euros Windows 8.1 Pro 18 euros Total : 616 euros I could have saved 10 euros on the graphic card (R9 285X 3Go), 30 euros on the box and 45 euros for a 600watts PSU. 616 - 85 = 531 euros not far from the 500 euros, if you already have the keyboard, the mouse and hard drive. But you can save 30 euros more with the FX-6300 though i'm not sure it's a good choice. For 531 euros you can get a pretty good configuration. If you go with a cheaper ATX box you can find cheaper motherboard and save money again so i think it's doable! The good point with the 700watts PSU is that i'm ready for crossfire. I will probably try this summer with an R9 380X which should be ok for the oculus.