I have a first gen intel i3 in a Silverstone SG01 serving as a HTPC for more than 5 years now. I have decided to repurpose that computer into a decent gaming rig capable of running Project Cars with most settings at medium at 60 FPS. I replaced the CPU with an AMD FX-6300 and added an old ATI 7950 GPU. I also replaced my drive with a 250GB SSD drive and added 4GB of memory for a total of 8GB.
I have overclocked the GPU but the CPU is running at stock speeds at the moment. This might be dinosaur aged, but it basically has the same 3D Mark score when compared with a budget build I made for a friend which has a Skylake i3 6100, DDR 4 memory and a GTX 960 GPU.