@mclaird - PCI-E risers should be available on ebay or other similar shop. I bought it on polish e-bay like site.
@Ludovic - your'e welcome
@mate - I made one thing wrong. Mo-BO.
Next time I'll do a bigger rebuild I'll go for a server type like one of ASUS Z9 motherboards.
The 16GB RAM limitation didn't exist for me before. Now it does
But 3D graphics, as I see along the time, can consume monstrous amount of money and may never stop
