Yes, it will work. But you do so at your own risk. I had that same 240W PSU in my Dell Optiplex 790 SFF (identical to yours) and installed a low profile GTX 1050 Ti in it. I had no problems running it and the CPU at 100% usage for all the time I owned the PC. But be aware that the +12v rail is only rated for 17a. My Kill-A-Watt meter indicated I was right at that range when maxed out gaming. Fortunately, I think Dell under-rates their PSUs.