GPU / Mobo Gurus - 3 PCI-e X16 slot vs 4 slot mobos

[DrPop]

Figure I'm going to have to bite the bullet and upgrade my mobo. When the RMA replacement for this one (http://www.newegg.com/Product/Product.aspx?Item=N82E16813130275&Tpk=870a-g54) comes in, I may just sell it on Ebay or upgrade Kat's rig with it.

I'm looking at 3 and 4 PCI-e x16 slot mobos for AMD's AM3 platform (specifically to run the X6 1090t and hopefully have some headroom to O/C it if possible!).

Here's what I can't figure out. Nearly all - if not all - the 4 slot mobos have the last slot as a PCI-e x16, so I would need a case with 8 or 9 slots open in the back to run the 4th GPU. LAME. Why didn't I realize this when I bought the HAF-932? The HAF-X has 9 open slots in the back. My now lowly HAF-932, the giant beast that it is, has only 7. Stupid. I don't think I'm close to ready to shell out another $140+ for another case, either.

So...am I better off saving the money and getting a 3 slot mobo, and just being happy running 3 GPUs (speaking of the future, I do NOT have the funds to purchase more GPUs right now.)

[Maxwell]

I think I've talked with you about this via PM (in roundabout ways), but my feeling is that you should just go ahead and get something with the 3 PCIe slots. You're going to have a hell of a time getting a stable 4 GPU system, and with the cards butting right up next to each other, you're going to have heat issues.

When I built the Silver Hammer, I only went with a dual PCIe slot Mobo, and haven't regretted that decision.

My two cents...:p

[Fire$torm]

I would recommend just going with a 3 slot MB. Tuck the saved cash away for a rainy day.
Question: Have you tried looking for a factory refurbished HAF-X? If you could find one at a good price then you could sell the 932 on eBay or keep it for that rainy day.

[DrPop]

I think I've talked with you about this via PM (in roundabout ways)...

I'm sure you probably did at one point when I was building up the first rig. Sorry, my life's been a little crazy lately, and not much room for storing information like this in my brain for months. :D

@ Fire$torm too - I think my main thing is, at a minimum, I want to be able to run 2 5970s at some point, and maybe a third one - or a 5870 in the third slot if I must. Other than things like the PG Challenges, I can't see the purpose of running tons of rigs, if all the points come from the GPUs (I'm not an MM guy)...I just need to run mega GPUs out of my mega tower I've got sitting here. :D Actually, I just don't have a lot of extra room at the moment for a bunch of boxes...

So, that sounds good. I'll look for the best 3 slot mobo - shoot, even 2 slots is probably fine if I could do 2 5970s, that would be a beast in itself...but has anyone tried 3 5970s? =:)

[Harley]

So, that sounds good. I'll look for the best 3 slot mobo - shoot, even 2 slots is probably fine if I could do 2 5970s, that would be a beast in itself...but has anyone tried 3 5970s? =:)



I'm running 2x5970's. I've never heard of anyone running three. The first problem I see is that I believe crossfire can only handle 4 gpu's, which would be 2 5970's. The 5970 only has one crossfire connection per card so you cannot link a third card even if you wanted to. I have no idea how CCC would react if you tried to 2 in crossfire and the third card with a dummy plug. Would CCC even recognize the third card, gpu 5 and or 6? :-??

The second problem I see, also connected to the fist problem, is that some people have reported that they are unable to run any projects unless crossfire is enabled. So leaving crossfire off and having the first card connected to a monitor and the second and third cards with dummy plugs may not work.

There are other problems with 5970's. Such as, I cannot run DNETC on my system. Other people have no problems with DNETC or only minor ones, stuck wu's or an occasional error. It just seems to be the luck of the draw when it comes to these cards.

On the brighter side I can run my cards oc'd at 950 (standard is 725) 24/7 on MW with no problems.

[Fire$torm]

I'm running 2x5970's. I've never heard of anyone running three. The first problem I see is that I believe crossfire can only handle 4 gpu's, which would be 2 5970's. The 5970 only has one crossfire connection per card so you cannot link a third card even if you wanted to. I have no idea how CCC would react if you tried to 2 in crossfire and the third card with a dummy plug. Would CCC even recognize the third card, gpu 5 and or 6? :-??

The second problem I see, also connected to the fist problem, is that some people have reported that they are unable to run any projects unless crossfire is enabled. So leaving crossfire off and having the first card connected to a monitor and the second and third cards with dummy plugs may not work.

There are other problems with 5970's. Such as, I cannot run DNETC on my system. Other people have no problems with DNETC or only minor ones, stuck wu's or an occasional error. It just seems to be the luck of the draw when it comes to these cards.

On the brighter side I can run my cards oc'd at 950 (standard is 725) 24/7 on MW with no problems.

You are correct in your first point. In a 5970 there is already a crossfire type of connection in the card. That's how they get to have 2 GPUs on a single board.
Which might be the reason a system with dual 5970s requires CrossFire to work since CrossFire is already enabled internally within each card and relates to point #2.

I believe your second point depends on the motherboard in use as its the support chipset that is a big factor.

To your third point, I haven't a clue as to why DNETC won't run for you. More than likely it too is related in someway to the chipset. I would suggest reviewing all your BIOS settings especially any settings set to automatic or auto-config.

[Maxwell]

+1 to what Harley said.

My 2x5970 rig does run DNETC. I get quite a few errors, but they usually happen fairly quickly, and the box still can do ~1M/day. However, I can't clock mine above 825 or all hell breaks loose.

And if you want to ever entertain 3x5970, you're going to need a TOP of the line Mobo...

[Harley]

You are correct in your first point. In a 5970 there is already a crossfire type of connection in the card. That's how they get to have 2 GPUs on a single board.
Which might be the reason a system with dual 5970s requires CrossFire to work since CrossFire is already enabled internally within each card and relates to point #2.

I believe your second point depends on the motherboard in use as its the support chipset that is a big factor.

To your third point, I haven't a clue as to why DNETC won't run for you. More than likely it too is related in someway to the chipset. I would suggest reviewing all your BIOS settings especially any settings set to automatic or auto-config.




The funny thing is, I can run projects with crossfire off and using a dummy plug.

I never considered the MB chipset. I have a MSI Big Bang Fuzion MB, any ideas?

I was thinking that it may have to do with the card's BIOS. I did have to flash the cards when I first got them to get manual fan control. Even running only one card in the box I still have some problems with DNETC.

[John P. Myers]

So once again, we come down to this Gigabyte motherboard (http://www.newegg.com/Product/Product.aspx?Item=N82E16813128441) lol
7th slot is a PCI. It'll handle 3 5970's np. Get it and be done scratching your head.

Don't worry about figuring a way to stick something in the 4th PCIe slot (unless you want to get 4 of these. (http://www.newegg.com/Product/Product.aspx?Item=N82E16814130601))

[DrPop]

So once again, we come down to this Gigabyte motherboard (http://www.newegg.com/Product/Product.aspx?Item=N82E16813128441) lol
7th slot is a PCI. It'll handle 3 5970's np.

Right. I understand that, but my point was that it's a 4 PCI-e slot mobo, and you can only put in 3 GPUs. (Only 3 of the slots are "usable" for GPUs). It doesn't seem like you can get many where you can put 4 in.
I may end up getting that board, it's a good one - but I just didn't like the fact that you're paying a premium for 4 PCI-e slots over a 3 slot mobo...but you can only really use 3. Hope that makes sense.

I did find a post here, half way down the page showing a pic of a rig with 3 5970s in it. (water cooled, though)
http://www.bitcoin.org/smf/index.php?topic=3032.20

Interesting, so I guess it can be done. Whether or not it would be worth the effort, I don't know.

[John P. Myers]

Why do you say you can only use 3? You can use all 4, as well as the PCIe x1 and the 2 PCI's with GPUs if you want. Also here's this statement from the Features: 4 PCI-E 2.0 x16 interface with ATI CrossFireX support for ultimate graphics performance

How else would you get quad SLI or xfire without using double-GPU cards? :p

[Harley]

My 2x5970 rig does run DNETC. I get quite a few errors, but they usually happen fairly quickly, and the box still can do ~1M/day.




I'm jealous!!! That was my dream when I got the cards. [-O<

[Maxwell]

I'm jealous!!! That was my dream when I got the cards. [-O<
Then you got to figure out your DNETC problems. You cream the crap out of me when we're both on MW... ;)

[DrPop]

Why do you say you can only use 3? You can use all 4...
How else would you get quad SLI or xfire without using double-GPU cards? :p

I think we just have a simple misunderstanding going on. You are correct, I should have re-phrased my post to say "you can only fit 3 double wide GPUs". It's the layout of the slots, the third one becomes unusable if you have double width cards.
Hope that clears up what I was thinking. I'm not doubting it's a sweet board. I would totally get one if I had the funds.

[Harley]

Then you got to figure out your DNETC problems. You cream the crap out of me when we're both on MW... ;)




I've tried everything, almost. Thanks to F$ I may have 1 more option. Have to wait till the charity challege is over to try it. ;)

When you put all your cards on MW I don't stand a chance. ^:)^

[John P. Myers]

I think we just have a simple misunderstanding going on. You are correct, I should have re-phrased my post to say "you can only fit 3 double wide GPUs". It's the layout of the slots, the third one becomes unusable if you have double width cards.
Hope that clears up what I was thinking. I'm not doubting it's a sweet board. I would totally get one if I had the funds.

Oh right gotcha. for a sec i thought that's what you were saying, then i had a brain fart and thought something else :p

I don't know what you paid for the mobo that caught fire or what the price difference would be after selling that to upgrade to the Gigabyte, but i can assure you you'll never have another issue until you want some futuristic chip that requires a motherboard upgrade :p