@ Argo82
Although there is always room for improvement moving forward (as others have posted), I think you are not too badly placed to get started, vMix is very efficient with its use of resources, whether the latest top-of-the-line, or even older middle of the road systems. Yours is by no means "middle of the road", just a little older.
The only concern I might have is with the x99 Motherboard chipset, as discussed in this thread:
https://forums.vmix.com/...aspx?g=posts&t=8456
However, if it's working relatively well for you with vMix and/or Wirecast, you are probably one of the lucky ones and can still get some more life out of your system for the time being.
There are many vMix users that are still on first and second generation Intel i7 CPU's as well as earlier generations of GPUs (I know cuz I'm one of them). Higher clocked CPUs and higher end NVidia gaming GPUs will go a long way at keeping vMix relevant and reliable.
When Render Times get above 20 ms and Total CPU usage gets above 70%, that's when you'll know you are underpowered to do what you want to do with your system and vMix.
Resolutions and Framerates undoubtedly have an impact, as do recording formats and how many camera, NDI and video Inputs you have, hardware encoding can help a lot with easing the load on the CPU for streaming and/or recording and fortunately for you, that option is available with the GTX 750 and up.
I would encourage you to push your system to the limit in testing to know where you may need to make immediate improvements or at least know where to draw the line for actual productions, you'll never regret testing and retesting and then testing again.
Just my thoughts.
Ice