Hi there,
according to my headline I want to build my own heterogenic HPC-Cluster but I don’t know how to do this!
The reason why is very simple - I need more CPU-Power and RAM^^
[MY CURRENT PC-COMPONENTS]
OS: Win7 x64 ULTIMATE
MOTHERBOARD: Asus Maximus IV Extreme-Z
CPU: Intel i7-2600K
GPU: Nvidia GeForce GTX 590
RAM: GeIL DIMM 4x8GB DDR3-1333
…
[IDEA ABOUT CLUSTER]
[QUESTIONS]
Thank’s in advance for all helpful answers. 
Um…I just did a bit of research and according to what I found, that Intel processor in your workstation is a 3.4GHz (overclockable to 3.8), and not 13.9GHz.
If I’m not mistaken, you’re probably getting that result by multiplying the processor speed by the number of cores - in this case 4. In reality they don’t really combine, they simply run at the same time, often doing different things. For instance take 4 cars on a highway, each going 100km/h - they aren’t going 400km/h total, just 100km/h individually.
Hope that helps a bit 
There are probably a few people here who can help with the renderfarm aspect of it and how to set it up.
EDIT - Also that picture is great, nice and clean