Scoping out new 4xGPU or 6xGPU 1080 FE build

[tachsah_boon]

I've been reading the forums trying to get an idea on what I can build for around or slightly over $5,000 USD.

I'm debating between a 4xGPU or a 6xGPU (both using open air rigs). The two items I am stuck on is which card to use and riser vs direct to motherboard connection.

I have a few questions:

Connectivity:
From some experience on an old rig build and also from the forum here I've read that  risers are bad--they do seem too cheap to be reliable (to me anyway). Is there a high quality riser option available?

Are the ribbon expansion cables a decent alternative?

Video cards:
Is there much of a difference between different founders editions?

Asus 1080 Founders Edition ($849.99 currently):
http://www.newegg.com/Product/Product.as...85V4XF1431

Vs:

EVGA 1080 Founders Edition ($699.99):
http://www.newegg.com/Product/Product.as...6814487243

If I have to choose between a flaky 6xGPU with risers and a more stable 4xGPU with directly connected GPUs, I will go with the 4xGPU.

Any other comments of suggestions would be greatly appreciated.

[epixoip]

I'd stay away from risers unless you have a lot of previous experience with them.

[jodler303]

i'm happy with these: (rig targetted at slow hash types)
http://eshop.sintech.cn/pcie-express-1x-...p-892.html

however, please consider the following:
a) be aware of the fact those are x1 risers. for certain operation modes of hashcat they are just fine, for others you might want to use x16 risers. - depending on your usecase.
b) i'm running 5 cards and all the risers on *one* 2000W PSU. - if you're planning to use multiple PSU's in parallel you might have issues.

therefore:
if you want a "setup and forget" configuration without fiddling around, i'd rather stay away from risers, as epixoip said.

[kiara]

Video cards:
Is there much of a difference between different founders editions?

Asus 1080 Founders Edition ($849.99 currently):
http://www.newegg.com/Product/Product.as...85V4XF1431

Vs:

EVGA 1080 Founders Edition ($699.99):
http://www.newegg.com/Product/Product.as...6814487243

nothing, they are FE = reference cards ,the only thing that change is the brand name.

personaly i would go for EVGA they have good reputation for their warranty

why not going for a mobo with enoought pci slots that u can shove these 6 gpu?
if u are going for evga u will save 900$ (for 6 cards), for that amount u can get a decent mobo with enough pci slots and another card

[tachsah_boon]

Thanks for the help everyone.

b) i'm running 5 cards and all the risers on *one* 2000W PSU. - if you're planning to use multiple PSU's in parallel you might have issues.

My current rig does have stability issues, but it has risers and also dual power supplies. What problems can dual power supplies cause?

why not going for a mobo with enoought pci slots that u can shove these 6 gpu?
if u are going for evga u will save 900$ (for 6 cards), for that amount u can get a decent mobo with enough pci slots and another card

Any recommendations on motherboards that I should look into?

[kiara]

i dont have any recommendation,
6 slot
http://www.newegg.com/Product/ProductLis...0600272332
7 slot
http://www.newegg.com/Product/ProductLis...0600307108

if i were u i would go for the mobo with 7 lanes, i have to mention that u will need to remove the black plat of the cards, and have some serious cooling inside

[tachsah_boon]

if i were u i would go for the mobo with 7 lanes, i have to mention that u will need to remove the black plat of the cards, and have some serious cooling inside

Yeah, that would be more customizing than I want to get into.

A few of things I am currently trying to sort out, maybe someone can help:

1. What is a good single power supply to go with to power 4xNvidia 1080 FE cards? I have a couple ax1200w corsair power supplies from an old rig, but that doesn't seem like enough if I go single 1200w power supply on my new build. The Nvidia 1080 FE card is spec'd at 180w, so 180wx4=720w, the motherboard and cpu, ssd, and fans would probably be around 350w? which would put me around 1000w utilized. Should I get a 1600w instead of using my 1200w?

2. What problems can a dual power supply rig run into? I wonder if that was part of the instability problem with my older rig.

3. As far as the 4xGPU full length pcie slot motherboards go, is there anything to watch out for or avoid? It seems like these are normally used for gaming. Are there any motherboard brands/models that are better than others for what I am looking to build?

Thanks again for all the help.

[kiara]

since u have couple of psus

https://www.youtube.com/watch?v=erHoq3DbwVA
and
https://www.youtube.com/watch?v=FWplSo4JgzI following https://www.youtube.com/watch?v=ouTEaMxJKJo

OR just bridge the green wire and a black wire on ur second psu with a metalic wire (or anything that conductive), this will power on the psu

[tachsah_boon]

since u have couple of psus

https://www.youtube.com/watch?v=erHoq3DbwVA
and
https://www.youtube.com/watch?v=FWplSo4JgzI following https://www.youtube.com/watch?v=ouTEaMxJKJo

OR just bridge the green wire and a black wire on ur second psu with a metalic wire (or anything that conductive), this will power on the psu

Right now I have the basic green one that was shown in the first video (on the old rig I am replacing). I thought I read somewhere that two power supplies was flaky, is that not true? Thanks!

[tacohashcat]

https://www.supermicro.com/products/syst...8GR-TR.cfm
This houses 4 GTX1080FE very well. There is a utility to change fan speeds on the case fans (the ones on the rear of the case are only used for passive cards like the teslas in the picture so you won't need it) also has optional rack mount rails which is nice. This case with 4 1080FE will get you in right at your 5k budget.