Re: i7 3970X (the most powerful intel cpu from that gen) isn't supported. Is it limited by chipset itself or due to power consumption and weak power supply? X series cpu require a completely different socket (and different chipset).  This one needs LGA2011.  It is used in Dell Aurora R4.  790 uses main stream socket lga1155. For RAM I would give it maximum. 16Gb listed but the real supported amount is 32GB I read somewhere. Please correct me. yes 32= 4x8 GB is doable.  Just make sure 8 GB ddr3 spec is non ECC desktop only 1333 MHz. For GPU I really don't know. Do you think that nvidia gtx1070 would be ok, if I replaced the original supply for stronger one? What do you think about upgrading this computer to its maximum? for gaming no real need to go beyond 16 GB.  32 GB looks better on paper but has no tangible benefit in gaming.  Save the investment for a better gpu. Cpu is old Sandy bridge Intel 2nd gen which limits performance boost potential.  There is still a lot of game one can play with i7-2600 and compatible gpu, just not as great as some faster cpu/gpu depending on settings/resolution. A 4th gen cpu/motherboard (e.g., XPS 8700, optiplex 9020) would better match 1070/1080/1080Ti. Stock psu needs to be upgraded for powerful gpu.  
Hello, recently I got Dell Optiplex 790. I like it but I want it stronger with more power. In PC there is currently i5 2400, in list of supported procesor, the most powerful CPU listed is i7 2600. But for example i7 3970X (the most powerful intel cpu from that gen) isn't supported. Is it limited by chipset itself or due to power consumption and weak power supply? For RAM I would give it maximum. 16Gb listed but the real supported amount is 32GB I read somewhere. Please correct me. For GPU I really don't know. Do you think that nvidia gtx1070 would be ok, if I replaced the original supply for stronger one? What do you think about upgrading this computer to its maximum? Thanks for all answers and help
Dell Optiplex 790 maximum upgrade