Gotta be careful if you are looking at SFF desktops and/or laptops. I'm pretty sure most of them have the low wattage CPUs and will throttle the processing power to maintain that wattage, IIRC.
16 slots of RAM and a Xeon processor screams power workstation or a server, I'd take that all day over a low-wattage 12th or 13th gen Intel Core i9. The desktop versions (full wattage) are heat generators, they basically require at least an AIO for cpu cooling. I don't see much of a reason to get an i9 these days, but if you have the proper cooling, why not I suppose. You could under-volt them in the BIOS settings with a motherboard capable of doing that to help with cpu temps.
16 slots of RAM and a Xeon processor screams power workstation or a server, I'd take that all day over a low-wattage 12th or 13th gen Intel Core i9. The desktop versions (full wattage) are heat generators, they basically require at least an AIO for cpu cooling. I don't see much of a reason to get an i9 these days, but if you have the proper cooling, why not I suppose. You could under-volt them in the BIOS settings with a motherboard capable of doing that to help with cpu temps.