So, I decided is still not to late to mine Ethereum and because I had some money put aside I went for it. The adventure so far was not as easy as I imagined, so you have below some advice in case you want to do it yourself:
Consider the size of the GPUs. I brought 2 MSI Sea Hawk Nvidia 1070s with water cooling. They are huge and I have to keep the cage open. The water cooling is really doing it's job on the other hand, I'm having low temperatures, good overclocking and a stable system.
Consider the power source and cables. The MSI Sea Hawks 1070s, each needs one 8 pins and one 6 pins power cables. Most power sources on the market don't have that many cables. I used some converters to switch from Molex but I can't put more than 2 GPUs with my source.
I bought another PSU, a modular one. It was a cheap one and it got burned. Got my lesson, the second PSU is a Gold certified Corsair. Paid twice for less watts but the system is stable.
Don't mix cables from different PSUs. Just don't.
In order to start the second PSU I just used a simple thing as seen below:
I bought a motherboard with 3 PCIE 16x slots and another 3 that can be used with risers. A waste of money that was, as 3 huge GPUs won't fit. People say that even if they would have fit, it would be too much heat generated and it won't be a practical setting. That being said, two 16X PCIE would suffice.
Isolate the problem by adding one GPU at a time. Otherwise you will
losespend countless hours of fun.Risers need power as well. Otherwise they won't work. Count them as well when you buy the power source.
Risers again. Buy more than you think you need. They are number one issue in most cases. Advice I didn't listen at the time. One of my risers was faulty and that made me try all the things below:
-- change PCIE slots
-- change cables
-- change GPUs
-- change mining software
-- change drivers
-- change operating system. I am using Win 10 with latest updates and it was as stable as it could be. But the riser got me into some blue screens I never seen before (and after changing it). For the fun of it I tried 2 Linux flavors (OpenSUSE and Ubuntu). Riser blocked them as well.
- The risers that worked for me are version 006C. It is said to be the most stable version of risers. The one that was faulty was version 007. The name is Riser. Faulty Riser.
- And a last advice. Just ignore that SATA to 6pins converter cable that comes in the riser's package.