not much boost in gaming performance bth i5-4590 n i7-4790.  difference between  i7-4770 to i7-4790 is minimal. i7-4790k otoh is the king pin.  It has a higher 4.0ghz base frequency, which is superior to 4790/4770 and can be helpful in a motherboard that cannot overclock cpu.  The k cpu is the cream of the crop in silicon binning. but the real crux of gaming upgrade is always gpu. consider upgrade GT1030 rather than cpu in 7020MT.  Get a 1650, 1050Ti, 1050 which are significantly better than 1030.  If you upgrade to XE2 365W psu then upgrade gpu to 1650Super or 1660. PS downside of used 4790k is unknown history and potential abuse risk.
Hello, I have a question about what processor is best to put in the Optiplex 7020 MT. I know that the best I can have in this computer is i7-4790 but a lot of people advised me i7-4770 because it is cheaper and slightly less efficient. The processor would be used mainly for playing games like Minecraft, Phasmophobia, Fortnite, Warzone 2 and slightly weaker titles. computer specification:i5-459016GB ram 1600MHz DDR3256GB SSDGigabyte GT 1030 OC ​​(overclocked by MSI Afterburner)290W PSU if the power supply had a problem with the new processor or you have any other suggestions, I'd love to hear them. Thanks in advance for your help.
Optiplex 7020 MT, CPU upgrade choice?