For those who want to also upgrade your computer, here the components are installed and running properly with me / do not have any compatibility issues:
Processor: Intel Xeon E3-1241V3 4x 3:50 GHz (Turbo 3.9 GHz) Socket 1150
RAM: Crucial PC3-12800 DDR3-1600 CL9 16GB KIT Ballistix Sport 2x8GB
Graphics card: Sapphire Radeon R9 280 3GB
HDD: 128GB Samsung SSD / 3TB Western Green HD
Sound: Creative Sound Blaster Z
PSU: Thermaltake Smart SE 730W 80 Plus Bronze (provision for power-hungry high-end graphics cards, and it is certainly too large;))
Update 20:02 - still no problem in terms of stability / not a single crash :)