DT psu is 250W.  DT blue PCIex16 slot max power is 50W.  Gpu upgrade quite limited. Better move all components into a mini tower case in which you will have freedom to upgrade psu with two 6 pin power connectors and install full height gpu. If you look for cheap used components on sale, generic MT case around $20 ATX 500W psu around $30 GTX 970 around $100 if you can find a good deal. If your current cpu is i5-3###, you may consider upgrade to i7-3770 depending on how the gaming app runs with i5.
which card is the best for a Dell optiplex 7010 DT? is the AMD Radeon RX 550 a good card? but most cards don't fit in this slim PC and my budget is about 150 dollars. what will I do? I want to card for good gaming which can play games like Gold Rush the game Farming Simulator 19 fishing North Atlantic and Microsoft flight simulator.
Dell optiplex 7010 DT GPU upgrade