I wouldn't go for the 1900x, if you were to go that route you would be better off saving a little on the platform and going with a R7 2700x and an X470 board. I am guessing you are after the quad channel RAM support on X399. Do your research very carefully with RAM, even now it's still hit and miss, particularly on Gen1 Ryzen/threadripper.
The specs look solid. That optane drive is going to add a lot to the system cost. Based on the fact that you didn't go right for the 1950x I figure you are working with a budget. The best advice anyone can give you is do your research on every component you are thinking about. Is optane going to benefit you to the point it justifies the cost for example. If yes, put a tick next to it and move on to the next component. Look at reviews that cover similar workloads to your needs. It has been a while since I last put together purpose built systems but these are the steps I followed every time. What do you need it for, what will benefit you most, what is excess and how does it all fit into the budget.
Personally, I wouldn't waste time with Optane, its fast as all hell yes but how much difference will it make to your workflow? You want to build the system to cater for both work and gaming so that tells me it is your personal system. If you are using your personal system for work then you are either self employed or running a small business of your own. The only reason to go with things that speed up workflows is to allow more work to be done in a finite period of time. If you are slammed with work and these time savings are going to pay for themselves over time then certainly go for them but if not, put your budget to better use.
I would go with:
1950x X399 Taichi/Fatality (whichever pleases you aesthetically) RAM from the QVL list, it wouldn't hurt to confirm with ASRock if the model you choose will work, send a support ticket to ask. 2x 512gb NVMe SSDs (samsung Evo or equivalent) Backup mechanical drive 8gb Seagate Ironwolf or WD equivalent GTX 1050ti or RX 560 (if you are planning to upgrade don't waste more money than you need to for playable FPS in games) That PSU should be fine
That should do what you need it to, cost you less and be easily upgradable. The Samsung NVMe options are fast, not speed demon fast like the optane maybe but they will hurt your wallet a hell of a lot less for a comparatively small decrease in performance.
That is my 2c for what it's worth
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