7 GPU set-up

I am investigating a set-up for GPU password cracking.
The GPUs in Chassis B would be connected via riser USB3 cables.

Chassis A (rackmount):
GPU: R9 290X (x3)
CPU: i7-4790K
Case: Chenbro RM41300-FS81
PSU: Lepa G1600-MA 
Mobo: MSI Z97 GAMING 5

Chassis B (rackmount):
GPU: R9 290X (x4)
Case: Chenbro RM41300-FS81
PSU: Lepa G1600-MA 

(+ cooling, + RAM, + risers, ..)

Is the motherboard fit for this? Would the CPU be able to support the 7 GPUs? Is it possible to go beyond 7 GPUs (by using splitters)?
Is there anything else that I'm missing that could cause problems?

I'm trying to go for the most cost-effective solution, alternatives are most welcome! Smile

Many thanks,
Either you need powered risers or just get Nvidia cards. GTX 980/Titan X
Thanks. I'd like to stick with the R9 290X ones as they're slightly cheaper, unless there's a card comparable in performance for about the same price.

Would this motherboard allow me to attach 3 (max 4) GPUs to it directly without using risers (while still using powered risers for the cards in chassis B)? I'm afraid it won't fit in the chassis otherwise.
You don't want to run 290X without powered risers. Else prepare to replace your motherboard every year.
(07-16-2015, 12:54 PM)ce3c Wrote: I'd like to stick with the R9 290X ones as they're slightly cheaper, unless there's a card comparable in performance for about the same price.

That would be the GTX 970.

There's absolutely no reason to even consider buying AMD for a new build.
You keep saying that but for those of us mere mortals who want great performance but don't want to shell out 15 grand or more for a TYAN GPGPU chassis + 8 Titans; 4 295x2's will get you 70% of that performance, work fine with consumer grade motherboards, and cost roughly 20% of the Titan X setup. Sure there's a bit of investment in power and cooling.. but its still the most powerful setup you'll find within enthusiast price ranges.
No. No. No. And also no.

First, I just recommend the GTX 970, not the Titan X. I never mentioned the Titan X in this thread, nor did I mention anything about the Tyan chassis. In fact, rarely do I even mention the Tyan chassis on these forums.

Second, even when we were recommending AMD GPUs prior to Maxwell, we never once recommended that anyone buy the 295X2 because it is a horrible card for oclHashcat. We always recommended that people buy 2x 290X instead of 1x 295X2.

Third, the 295X2 is the same price as the Titan X, is roughly the same speed as the Titan X, and yet requires 2.5x more power than the Titan X, doesn't work well with oclHashcat, has braindead firmware, requires watercooling, and grossly violates the PCI-e specification. So no, 295X2 is certainly not the way for enthusiasts to go. I'd take a Titan X over a 295X2 any day of the week, and 4x Titan X rig would definitely be the ultimate enthusiast rig -- less money than your 4x 295X2 rig even, since you could easily power the whole system on a single 1400W PSU.

Fourth, bringing this thread back on topic, the OP wants to build a 7-GPU rig. I recommended he use the GTX 970. 7x GTX 970 is half the price of 4x 295X2, requires 62% less power than 4x 295X2, and yet would only be ~17% slower than 4x 295X2. 7x GTX 970 also won't be causing any fires anytime soon, while the 295X2 is just a fire waiting to happen (250W through a single 8pin!?!)

So I stand by my assertions. There's absolutely no reason to buy an AMD GPU for a new build -- regardless of whether you're a professional, an enthusiast, or a hobbyist. Nvidia is just plain better on every level.
I found your benchmark gists comparing the GTX 970 and R9 290X, epixoip, really helpful.
The GTX 970 looks indeed better from all angles.

It looks I won't be able to buy the reference design of this card in Europe though. Do you know of any retailers in Europe that sell it? 

I'm looking into the following OEM designs now:

Do you also have a rough estimate of the wattage that the 7 cards would pull? (including/not including the rest of the system)

Many thanks for the feedback!
In your case it does not make any sense to buy seven GTX970. Buy 4 GTX980Ti instead, get the same GPU power but without the complication of two chassis, what btw saves you a good bunch of money. That's my advice.
The GTX 970 reference design is a unicorn, you'd be lucky to find one let alone seven of them. The ASUS card you linked to is a good card though. The estimated wattage for 7x GTX 970 is 980 ~ 1100 watts.

Hmm, I'm not sure 4x 980Ti is the same power as 7x 970. I'm too lazy to math right now though, so I'll just take your word for it Wink But I agree that going with 4x higher-end GPUs is better than 7x mid-range GPUs. I didn't realize he intended to split this between two chassis, but now that I scroll up I do see this.