I built this to hold me over during the inflated PC market last year (2018). I got the T3500 Desktop for 50$. I actually bought 5 of them at this price to upgrade and flip. This was in the better condition between the five that I bought, and I put a little more money into it than was necessary for the sake of enthusiasm. Since I did not have an overclocking motherboard, I opted for the 86$ X5690 over the 22$ X5660 for it's higher clock speeds (3.5Ghz vs 2.8Ghz). I added exhaust fans, removed all of the unneeded parts from the inside of the case, and added a GTX 1060 3GB.
The 1060 3GB was a neat card. It played League of Legends at 4K, but struggled on a lot of the games I wanted to play at 1080p, even on lower settings. To remedy this I replaced the 1060 with a 1070, which required a larger power supply. I was really happy with the 1070, and I kept this configuration for 5-6 months. I eventually sold the system for 450$ without the Wifi Adapter or Peripherals.
Here are the UserBenchmark Results:
Game 89%, Desk 54%, Work 53% CPU: Intel Xeon X5690 - 69.8% GPU: Nvidia GTX 1070 - 107.5% HDD: WD Blue 1TB (2012) - 87.4% RAM: Unknown 15GB - 44.6%