Seeking Lenovo / threadripper advice

I'm loath to give Apple more money, and considering upgrading to a Lenovo p620 with threadripper. I'll repurpose my nvidia 1080ti 's for now, to keep the costs down. My big question for the group, and I can't find this answer with google (my google jedi is weak, apparently): Is the socket the same for the 3945wx as it is for the 3975wx and/or 3995? In other words, if I start with a 55 to save money (16 core,) can I swap in a 75 or 95 later? (32 or 64 core.)

Any other tips on switching from mac to windows much appreciated.! For the price of the threadripper lenovo, I can get a used 2017 imac pro with an inferior GPU. My main apps are Resolve, then Avid media composer, then I'm forced by clients to use premiere from time to time.

tia

Responding to my own thread - Sales support says, yes, it's the same socket and memory config. I hope they're right! So, In a few months I can buy a 32 or 64 core threadripper and just swap it in. Fingers crossed! Lenovo USA had a pretty good holiday weekend sales price, and pre-configured systems, so there's no shipping delay like 90% of the custom builders! Fingers crossed.

I'm sure the return to Windows will be painful, but I used to be all-HP, so I'll get the hang of it...

IMHO, you did the right thing. While the new M1 machines are impressive, they are entry-level. Apple has nothing to offer right now in the price/performance range of a good PC desktop.

Anyway, once you started your programs, it'll feel more or less the same. Just be careful about Windows updating your GPU drivers behind your back. If anything goes wrong with DR, that's the first place to check and just get the right driver directly from the manufacturer's site.