Today, I sold a refurbished Dell Optiplex 990 with Intel i3, 2nd gen processor to a machine shop to run a fabricating tool. Pulled the i7 that was in it originally out, as he didn't need that.
I wanted the machine to have a standard 24 pin ATX power supply and the Optiplex 990 had that while a ThinkCentre and several HP machines that I had on hand didn't.
The machine shop is a dusty place and I want it to be as easy as possible for the owner to swap out the power supply should it fail in the future.