Cheap Windows Machine with multiple Cards

[eyelovemotion]

Hello folks

i have been a mac user for over 15 years now. I`ve done lot`s of motion graphics and 3D ( Cinema 4D) with GPU rendering.
Some time ago now i put a GTX titan with an extra external PSU ( Paperclip) in my mac pro late 2010 ( 12 Core)
I am still quite ok with that computer but i want more cards localy in my case under my desk!

which mainboard, processor, graphics card combination would you advice?
i thought ob buying 2 new cards, so that i can still use my gtx titan from 2013 (6GB)

Is that possible if i at least by two new cards with 6 GB VRAM on them each?
Or would it male more sense to by three new ones?

Which board and which processor would you recommend?

Thanks in advance
Cars

[smicha]

Read this for a general overview
http://tomglimps.com/value-based-multi- ... ne-render/