I am looking for a GPU for my Optiplex 990 Slim Line, I will be playing CS:GO, COD, Minecraft, maybe BF4.
Does your desktop support full sized PCI-E Adapters or is it one of those half/mini ones?
If it's the half/mini, then you're out of luck and options.
Not sure if it helps but I have this pc
Yeah that's the mini PCI-E Adapters in the back. No GPU other than the extremely cheap and weak ones are fitting in that case.