OTOY Forums

Diehard Mac user - but complete PC-builder noob here
I have looked through several forum threads but haven't found the answer yet and I hope some of you can help me out.
I have an EVGA GTX 980 ti Hybrid (water cooled) card now, but want to build a new workstation with this card + three 1080s when they come out.
I have an guy helping me select components and build it, but he doesn't have experience with multi GPU systems and since I am going to spend quite a few $$$ I would like to avoid mistakes

So my question is which motherboard would be good for this configuration?
Is a card with 5PCi-Express slots (like the MSI Z97 Power AC) be used or do I need another with more slots so I can leave some empty for better airflow or is there anything else I need to consider?
Budget is not a major concern since I will be using it professionally 40-60 hours pr week so even though I dont want to spend more money than I have to, it is more important that it works...
Sorry if this has been answered a million times before but Im completely new to this PC-build-thingy - Ive spent the last 15 years just selecting a Mac and clicking BUY

What is your cpu?

That will have to be decided.
I would like a 4GHz CPU (since many operations in C4D are single threaded I’d rather have high clock speed than many cores), but as I understand it it has to have enough lanes for all GPUs

So you don't have any components yet, except the hybrid card?

Thats (almost) right.
I have a PC with the hybrid card, but I will put in the original card, take out the HDD, sell that machine and build a new one.

I already have and will use the 980ti + Harddisk
The rest is new
3*1080
64GB RAM
suitable motherboard
suitable CPU
suitable PU
and all the other things.
But the main component is the motherboard and the four GPUs - the rest should fit around that...

All is about your budget. You may go with cheaper gigabyte
http://www.gigabyte.com/products/produc ... id=5332#ov
and 5930k - it must be 40 pcie lane cpu for this board.

1200W is enough but let's wait and see how 1080 will be power hungry - I think 100-150W in Octane.

With 4 gpus there will be hot but before going with watercooling on all of them let's wait and see temps under full stress on 1080.

Lately I built massive machines on Auss X99 E WS mobo but after what I've experienced I cannot recommend this board. I don't say it's bad for 4 GPUs, but it's not that good for 7. Only this year I RMAed 2 of them. The only advantage of it is full pcie x16 on 4 gpus, but you'll live with x8, especially Octane is not optimized yet for better bandwith on 6 or more cored cpus.

I'd go with X99 or if older X79. The ASUS WS-E boards etc, if you need fast bustransfer (x16). Those boards have PLX switches to grant more PCI lanes (4*16x,aka 64 lanes) to the slots, than the CPU has (40). But you usually don't require that bus speed for rendering I think. Even games do not profit much by gping from 8x to 16x.