Thanks for your answer.
Before buying the 3900x, I checked for cheap threadrippers, but at this budget the 3900x was the king. Actually no, on ebay you could find nice deal for 1950x and other but the performances of the 1 st gen threadripper are still lower anyway and when it comes to the 2nd gen, it's too expensive... until I stomped into those budget monster that are the e5-2690(+) v3-4... I actually regret my choice a bit... I feel like for the same budget I could have get like 20-30% more multi-thread performance, even easily beating the 3950x... I'll just save 700 euro and buy it all, compare it to my current build then sell the less appropriate build..
The opportunities I look was on ali express : https://fr.aliexpress.com/wholesale?catId=0&initiative_id=SB_20200929083718&SearchText=e5-2695+v4
Also, I am very new to Xeon cpu, so what are Haswell and Broadwell chips ?
I feel like going for a xeon build allow for more upgradability as you can always (1) buy a better cpu, (2) upgrade to a dual socket motherboard and just buying one extra cpu, (3) going for a quad socket and buying 3 more cpu... It seems so easy to upgrade.. And cheap.
Like, 4 wisely chosen Xeons could easily beat a 3970x, right ? 2 e5-2690 v4 score around 9100 on cinebench r10... with 4 of those you hit 18000 points for... 800$... Ridiculously incredible.
At the end I am really asking myself if third party xeon build wouldn't be always the way to go for multi-thread oriented build/workstation ?