Thanks for your fast reply @Juraj Talcik!
I could wait let's say until august - from what I understand Zen2 is lunching in july but release dates could extend quite a while (?)
There is a chance I will upgrade to 128 of ram indeed. I wasn't aware that poses a problem with Threadripper ?
No, oppositely :- ). It doesn't pose a problem with Threadripper.
Ryzen is AM4 platform, dual-channel right now, only up to 4 DIMM slots. Currently DDR4 (Non-ECC) modules only come in 16GB modules. So hence 4x16=64GB maximum. Samsung already started production of 32GB non-ecc modules, but when they will come and how they will be supported is currently unknown. There is no guarantee it will work on current motherboard simply with bios update. So if you go with Ryzen you might be stuck with 64 on X570 boards. In theory, maybe in practice both X570 and the higher-end X590 will support 32GB dimms (and thus 128GB option). Intel's LGA1151 is also dual channel quad-dimm socket only, and does theoretically support 32GB Dimms when they become available.
Threadripper, TR4 platform, is quad-channel, 8 DIMM slot (on ATX and E-ATX sized boards), so you can go up to 8x16=128GB, so if you buy 4x16=64GB now, you can buy another 6 months later if you wish.
Also, you could theoretically buy high-end TR4 board (only two of them, MSI MEG and Asus zenith ALPHA), both of which can be score for 500 euro, Alpha only if you search around... buy cheaper Threadripper now, and later upgrade to Zen2 32/48 core.
Zen2 Threadripper will come probably with its own new chipset (X599?) but will work on existing X399 chipsets as long as they have powerful enough power cascade. And only MEG and ALPHA have 16 VRM phases.
That's my suggestion number 1.
My suggestion two would be 16core Ryzen9 3950X, but in order to update 4x16=64GB memory, you have to upgrade fully to 4x32 in order to have 128GB in future, replacing what you already bought (64GB DDR4 3000 CL15 currently costs about 320 +/- Euro).