MartinVidic wrote:the motherboard doesn't have HDMI2 but the video card does. that should be ok, right?
Yes that's ok, in fact it's the way it should be connected.
MartinVidic wrote:1) that motherboard is the cheapest X299 one. I only use ONE 1TB SSD and one graphics card. I think i dont need any extras of the more expensive X299 motherboards, right?
I think your build is fine. If you don't need wifi or stupid rgb lighting a barebones x299 should be good enough.
MartinVidic wrote:2) I would like to start using the system with my old ram for about 1 month. but they are just 1600mhz. I know faster ram will work better with this processor and I will upgrade to 16GB with at least 3600mhz within a month. But can i use it with the 1600mhz ones at all for a month?
You can't. Your 1600mhz is probably DDR3 memory and the motherboard only takes DDR4.