I would get the 32GB but not more than 64GB because the RAM speed goes down when all the slots are used.  Whatever route you decide to go make sure it is dual channel. The 750W power supply should be enough but, I would actually get the 1000W PSU if it is available. Might wanna consider liquid cooling and getting the best video card you can afford.
Hello, I intend to buy an xps 8950 and am wondering about a few items specs to make it a compatible unit. I am going to use it for editing large file photos with Adobe Photoshop and Lightroom. Do I need 32 DDR5 or is 16 DDR5 enough? Do I need the 750 W power supply? I am going to elect the i7 12 gen intel core 17 127 ook 20 thread 3.6 to 5 ghz processors. Any suggestions? Richard
Buying a Dell xps 8950