Any downside to pairing a 6990 with 2x 6950s?

SaViOr-

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So going to be doing some upgrades towards the end of this month in hopes of being able to run Ultra settings in BF3 at 5932x1080 with 60+ FPS on the massive Conquest Maps (Caspian Border brought my system to a crawl on low settings in eyefinity). Right now I have 2 6950s in CF and was thinking about getting a 6990. Now I have a few questions.

Would I be holding the 6990 back at all by running it alongside 2 6950s that have 1408 shaders vs the 1536 of the 6990?
Would I be better off with selling the 6950s, getting a 6970 and only running tri-fire 6990+6970?
Option 3 would be to skip the 6990 and pick up 2 more 6950s and run Quad-fire with 4x 6950s?

Other Upgrades that will be done at the same time are Replacing my Pro board with a WS Revolution, getting a full tower case for better airflow/space & a 1200/1350w power supply.

*EDIT* Figured I'd updated the first post.


I've narrowed down it to two options with this upgrade:

Option 1
ASUS MAXIMUS IV EXTREME - Runs Triple cards at 16/16/8
Get a 6990 for Quadfire 6990+6950+6950
Cost ~ $1030

Option 2
ASUS P8P67 WS REVOLUTION - runs Quad cards at 8/8/8/8
Get 2 more 6950s for a total of 4x 6950s for Quadfire
Cost ~ $800

Power supply with either option will be the HCP-1200 or AX1200. Case will most likely be the CM HAF 932
 
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samuelmorris

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There would be some degradation, but very little. The HD6990's reduced clock speed means it's only a few percent different from a pair of 6950s. The only issue you need to consider is PCIe link speed. Three cards off a P67 board means a maximum of 4x link on two of the slots, which is fine for single cards, but beware of some boards that may cut it lower.
 

SaViOr-

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There would be some degradation, but very little. The HD6990's reduced clock speed means it's only a few percent different from a pair of 6950s. The only issue you need to consider is PCIe link speed. Three cards off a P67 board means a maximum of 4x link on two of the slots, which is fine for single cards, but beware of some boards that may cut it lower.

The board I will be getting is this http://www.newegg.com/Product/Product.aspx?Item=N82E16813131714 ASUS P8P67 WS REVOLUTION. It does Tri-fire at 16/8/8 and quad at 8/8/8/8
 

samuelmorris

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Better, though with Asus branding and an nforce 200 to play with, there are at least two of boxes ticked for an unreliable board - the newegg reviews are pretty scathing of late.
Also, remember with dual slot spacing you will have no spacing between your cards, meaning they will be very loud.
 

Tiporaro

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First - personally, if I was considering that serious of a setup, it would seem to be a perfect excuse to drop the extra on a Maximus board, which has just recently gotten pretty much the highest praise possible from this site in their review.

Other thoughts that come to mind for me:
1) You may have already, but if you haven't tried unlocking the 6950's, depending on the model that could eliminate some of your debate. Looking at the reviews of the Powercolor 6950 in your sig, it seems like it may be hit or miss unlocking it.
2) Cooling - Running 4 cards like that sounds like a potential hotbox. Not sure what your plans are for cooling, but tri-fire will put out some heat (whether 6990+50/70, or 3x6950/70), and 4 will probably need planning outside of your default setup to keep the cards running well. Much more so if you want to put a decent OC on them - I know if i were running quadfire, I'd want to =)

As far as choosing between those types of setups, I'd say the 6990 with the 2x6950's has the potential to give you the highest performance without headaches that I'd anticipate with the 4x6950, also assuming you are willing/able to eek some performance out of the 6950's. The 6990 + 6950/70 will probably be the least hassle, but will obviously be underperforming the quadfire setups if working properly. And the 4x6950 do have the possibility of outperforming the others, but I barely ever hear of someone running a 4-card setup for quadfire, so there may be unexpected issues, not counting cooling hurdles to overcome.

A final note, I do believe the scaling of xfire isn't quite as great for quadfire as it is at 2 or 3 gpus, so the drawback is, of course, that your price-performance is decreasing once you make the decision to go for 4 gpus in whatever configuration. However, I figure this is not a major concern once you're in the realm of factoring in a 6990. In any case, good luck, and let us know how it goes!
 

SaViOr-

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Hmm good point on the maximus board, its only $50 more. The only reason I chose the WS Revolution over the maximus was the fact that the WS can support quad cards while the maximus can only do 3. My cads weren't unlockable at all =/ tried the RBE shader only unlock but system wouldn't boot.

As for cooling I'll be getting a full tower case, either the HAF 932/942, Antec 1200 or Obsidian for more space and get some good case fans. I'll be running the card fans at 90-100% to help keep them cool too since sound/loudness doesn't matter at all to me since i game on headphones :).

Hmm looking at prices right now on newegg id save around $200-230 if I went with 4x 6950 and the ws revolution over a 6990 and the maximus board. Is the extra cash worth it to go with the 6990+ 2x 6950 setup? I'm assuming the latter would be cooler, more stable/reliable, etc?
 

Tiporaro

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I have my speculations, but honestly, I unfortunately don't have the first hand experience. At this point your best bet is to find some of the more "courageous" people here that have played around with quadfire, especially if you can find someone that has done the 4 card solution. Offhand, I remember reading some of Vega's posts on here, and I believe he has messed around a lot with some extensive setups in driving 3xU3011s in portrait eyefinity.
 

samuelmorris

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My quad crossfire experience only runs to the HD4 series, but from using that for two years I can confirm that it ran a lot better than most people expected :p Sure, not 300% scaling, but it got pretty close with a few games.
 

SaViOr-

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I've seen pretty great reviews from [H] and other places about Quadfire performance and scaling with the 6 series cards :).

I've narrowed it down to two options with this upgrade:

Option 1
ASUS MAXIMUS IV EXTREME - Runs Triple cards at 16/16/8
Get a 6990 for Quadfire 6990+6950+6950
Cost ~ $1030

Option 2
ASUS P8P67 WS REVOLUTION - runs Quad cards at 8/8/8/8
Get 2 more 6950s for a total of 4x 6950s for Quadfire
Cost ~ $800

Power supply with either option will be the HCP-1200 or AX1200. Case will most likely be the CM HAF 932

What do you guys think?
 

samuelmorris

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You might find heat a problem with four HD6950s cramped together - I'd probably say go the 6990+2x6950 route if you can afford the difference. 4-card CF has had problems with bridge connector bandwidth in the past.
 

blackhawk777

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I have been thinking about possibly picking up a 6990 and swapping it with one of my current cards but I'm not really interested in paying over $700 for it. Maybe when the prices drop a bit I'll take the plunge, but aside from that I do have input....

My setup is in a HAF932 case with the three cards stacked one on top of the other... there's no other way to fit three into the board. Now a few people have suggested that there might be too much heat with four in the case for the cards to run quietly, but in my experience that is not the case. I have my cards running at 920 / 1370 right now with the power increase set at 15% in CCC and they will all stay under 70C with the fan speed set to a constant 50%. You might even be able to get away with 40 or 45% depending on the room temp and size. I would be more concerned about the crossfire connector bandwidth issue that was mentioned above. I have seen more than one person mention that there is an issue getting enough bandwidth when four cards are set up together, and that's why I was going to take the 6990 route. If you do go with four 6950s I would love to see the performance numbers and hear your experience.
 

ekuest

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what about selling the 6950s and buying 2 580s? net spent would be around $600 and you wouldnt have to change mobos (needs a reformat :() plus no quadfire problems and probably less scaling loss. idk just a thought. not sure if you have an allegiance to amd or if you do something else with your comp that requires amd cards.
 

Matrices

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Buying 580s is a waste at this point. You're either saddled with 1.5 GB or you're saddled with high price for 3 GB version. Neither decision makes sense with Kepler around the corner.

Matter of fact, bulking up on any of these current GPUs is a waste, unless you have money to burn, because the parts due out in Q4 and Q1 2012 should be roughly twice as fast.
 

samuelmorris

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'Around the corner' being a good 6-9 months away. I wouldn't use Kepler as an argument against the GTX580, just its other disadvantages - primarily price.
 

SaViOr-

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what about selling the 6950s and buying 2 580s? net spent would be around $600 and you wouldnt have to change mobos (needs a reformat :() plus no quadfire problems and probably less scaling loss. idk just a thought. not sure if you have an allegiance to amd or if you do something else with your comp that requires amd cards.

I plan to run an Eyefinity resolution of 5932x1080 for BF3 so 2GB per card is the minimum that I'd be willing to go with. If i were to go with 580s i would have to pick up at least 3 of the 3GBs to match the performance of 6990+6950+6950 at that res, making the cost much more and I'd still need a new mobo :p.

Buying 580s is a waste at this point. You're either saddled with 1.5 GB or you're saddled with high price for 3 GB version. Neither decision makes sense with Kepler around the corner.

Matter of fact, bulking up on any of these current GPUs is a waste, unless you have money to burn, because the parts due out in Q4 and Q1 2012 should be roughly twice as fast.

The latest cards won't be out until Q1/Q2 2012 sometime and who knows when the supply will be sufficient enough to be able to pick up 2 or 3 new high-end 7000 series amd or 600 series nvidia without them being backordered or out of stock for months on end.

I just need something that will allow me to max out Battlefield 3 at the end of the month and enjoy some triple monitor gaming with 60+ FPS :). If the next gen of cards does turn out to be a big performance improvement over whatever upgrade path I go with then well, that's what we have a FS/T section for :D. Give someone else a good deal on these cards and pick up new ones.

I was very disappointed with eyefinity performance on the 64 player Caspian Border map in the BF3 Beta so some sort of upgrade is required in my eyes. Op. Metro Ran fine, but no dice on the conquest map. I realize that the game is in an early Beta stage but I doubt that they can increase performance to make me stay with just my 6950 CF setup, considering that I was only getting about 25-35fps on that map.

I think that I will go with the 6990+6950+6950 Option due to the fact that I have been doing some research on the quad card bandwidth issue with the CFX connectors that you guys mentioned. Might also change the HAF 932 out for a Corsair Special Edition White Graphite Series 600T Case since I won't need a full tower with just 3 cards and use the mesh to replace the clear panel & then add some 120mm fans for additional cooling for the vid cards
 
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samuelmorris

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This is truth, the 28nm cards are ages away yet, I wouldn't advise anyone to hold out for them, especially not for BF3 given its imminent release.
 
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unlock the 6970s OC to 6990 speeds that's what I'd do
 

SaViOr-

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Decided to sell off my 6950s in a couple weeks and then just get 2x 6990s for Quadfire. Reasoning behind this is that I want to eliminate any possible issues associated with using 3 cards for Quadfire rather than two dual-gpu cards. Trying to also eliminate any bandwidth or heat issues that may arise and if I went with 3 cards I wouldn't have anywhere to plug my sound card in lol.

Thanks for all the feedback guys! Really appreciate it
 
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blackhawk777

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Sounds like a great solution and I would think that two 6990s will be more than sufficient for a good amount of time to come. Good luck!
 

ekuest

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i was originally gonna suggest that, but then thought maybe 580s would be better just cuz you have 2 gpus instead of 4. completely forgot that they only have 1.5GB of vram. yeah 2 6990s would be great i think. why did you say youd still need a new mobo for 580s? will you still need one for 6990s?
 

SaViOr-

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i was originally gonna suggest that, but then thought maybe 580s would be better just cuz you have 2 gpus instead of 4. completely forgot that they only have 1.5GB of vram. yeah 2 6990s would be great i think. why did you say youd still need a new mobo for 580s? will you still need one for 6990s?

For 580s I would need 3 of them to equal/exceed the performance of the 6990+6950+6950 setup that I was originally going to get and my current mobo only supports 2 video cards. Going with the 2x 6990s also means that I won't have to upgrade my motherboard :D
 

Adam.C

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For 580s I would need 3 of them to equal/exceed the performance of the 6990+6950+6950 setup that I was originally going to get and my current mobo only supports 2 video cards. Going with the 2x 6990s also means that I won't have to upgrade my motherboard :D

Your right, and then because you are so nice, you will sell me your 6950s for $100 to me. Thanks man!
 
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itd be prolly easier to cool a two card quadfire setup than a 3 card one
 

SIRTIM3

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I am running Quad fire (6970's) on a ASUS P8P67 WS REVOLUTION, and I would not recommend it. Tri-fire is where its at. Reason I am running quad cause I took my 6970 out of my spare pc to test drive quad and for the most part there is very little gain. Games I can think of that scale well Hard Reset, Dirt2,3, Metro 2033 and Crysis Warhead. Games I know that dont scale F12010, Deus Ex, Crysis 2. Most other games show little improvement at all or simply dont use the 4th gpu. When it works its great, but that is not even close to the norm. If you had a spare one laying around or got one for a REALLY good deal then I would say ya, but the gains will be minimal in the majority of games..... Having said all that I do love this quad fire set-up just wish I saw better gains from it. Oh ya Im running eyefinity
 

Matrices

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Well I wish I could give a firsthand account but that will have to wait until the game comes out. My system was running BF3 test at 1080p x 3 like shit but I'm not convinced it was because of vRAM - I disabled SSAO/HBAO and came in at under 1500MB, yet the performance still sucked. Too many damn issues with this Alpha so-called Beta to draw conclusions.
 

SaViOr-

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Sell both cards and snag a 6990 and 6970. Still no MB cost and you get the full potential of your current system. What PSU do you have right now? You may be able to re-use that also.


*edit* Corsair 850, you'll still have to Upgrade. [H] pulled 811w without OC the cards on their review of tri-fire.

http://www.hardocp.com/article/2011/04/11/amd_radeon_69906970_crossfirex_trifire_review/8

I decided to sell off my 6950s in a couple weeks and then just get 2x 6990s for Quadfire :). current psu is the 850, but will be getting a Corsair AX1200 with the Upgrade. & since I won't have to upgrade my mobo I'll be getting the Corsair 600T SE in White and the Corsair H100 for some liquid cooling on the cpu to cut down on some heat in my case.
 

Tiporaro

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Should just go all out and build a custom loop for your new gpus as well as your CPU =).
 

SaViOr-

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Oh I'm not a fan of water at all. The only reason I'm even considering the H100 is because it's a closed loop maintenance free system & I want to eliminate some heat coming from the inside of my case so I don't have an oven in here in the winter time :p. There's still something about water inside my case with expensive pc components that doesn't sit right in my gut. My chip gets a little toasty running at 5ghz even with the NH-D14, most likely due to the extra heat coming from my video cards right now. Hoping that going with the H100 will help and I'll be able to push the OC a little further.
 
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