i5 750 is quite old. One of the gpu that matches this cpu is GTX 750ti. [URL] does not need a power connector. recommended psu is 300W minimum.  980MT psu is 305 W. You may get by with it because psu recommendation is often calculated based on i7 not i5.
Hello. I have Optiplex 980 MT, i5 750, 12GB ram, with GeForce 430 GPU. I'm running Linux Mint 19 Tara. I'm considering buying a GPU upgrade. Any ideas what GPU can be put in it that would significantly improve graphics performance? From what I understand this type of comp is quite problematic for GPU upgrades.
Optiplex 980 MT GPU upgrade?