Thank you very much Dimitris, Nikolaos and numerobis.
Yes, you are all totally right - i see now that there is no plausible reason in my case to opt for the Xeon and the Firepro W7100. Saving the money i should rather get more RAM, a bigger SSD and HDD as you say and a GTX970 which does the same job or even better.
So,the CPU/GPU decision is done : i7-5820K/GTX970!
Overclocking? - i don't know so far, no gaming on this machine intended.
But if there's a benefit for day-to-day work - maybe ;-)
@Nikolaos: thanx, that looks good. What do you think about the EVGA GeForce GTX 970 ACX SuperClocked ?
Do i really need Water-cooling?
@numerobis:
I haven't thought about the M.2 PCIe SSD so far. I just picked out the 512GB Crucial MX100 2.5" (6.4cm) SATA 6Gb/s MLC
(CT512MX100SSD1) for my new buildup. Well 32GB/s sounds great. I have to check the Budget again if 512GB is possible with m.2.
So far, thank you all. I think i will come up with my final decision in the next days.
bye, michael