6970 Crossfire Issue

Starslayer67

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Note: This is basically a rehash of my previous thread here; I'm posting this based on addictedto60fps's advice given there. Mods, please lock if I'm doing something wrong here.

That out of the way, my new 6970's have been giving me some trouble. Basically, Crossfire isn't playing nice. I've tested each card individually, and they both seem to work fine, but when I enable Crossfire, it either barely increases FPS, or worsens it. If the game is not too graphically demanding (i.e., is old), it'll hit 60 FPS and glide smoothly, but anything relatively recent causes an odd issue to happen: the master GPU tops out at about 60% usage, while the slave is all the way at 100% usage the whole time.

I emailed AMD Support about this, and they said it was probably the cards not getting enough power. This seems a bit odd to me, though, since my power draw never climbs above 550 W or so according to my UPS, and my X-750 puts basically all of its power down the 12V rail, so the cards should be getting enough juice.

I have so far tried both Crossfire bridges I got with my cards, and I have tried all drivers 10.12 and newer. Nothing has caused any change in my system's performance (the 10.12's just caused loads of crashes, btw). I currently have the 11.6's and the 11.6 CAP 1 profiles installed. All other system specs are in my sig.

If power difficulties are the case, I presume something like an X-850 or Corsair AX-850 would be enough, yes? And if my cards are fully powered, what is going on instead?
 

Rogue71

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your usp is reporting upto 550W. thats whats being drawn from the wall. that is not what your psu is outputting to your system. anyting from amount to quality of power being outputtted could affect system components. that being said i would think your seasonic 750 should be ample to provide decent power, assuming there isnt a problem with it.just to prove the point it might be simpler to swap out a psu and see what happens. some retailers allow returns with minimal restocking fees. ive taken advantage of that a few times when i didnt have a spare component to test things out. im currently running crossfire 6970s and havent had any issues. just curious....what games in particular are you having issues with?
 

Starslayer67

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I have so far experienced the bad performance with Dirt 2 and 3, Crysis, Metro 2033, and the Complete mods for Clear Sky and Call of Pripyat. HL2 and SHOC have been limited to 60 FPS by vsync. I notice no change in performance with vsync on or off. I should mention that this is all at 1920x1200; when I moved back to Eyefinity, performance cratered to 10-20 FPS for most things.

One thing that did strike me as odd as well was that each of my cards gave me worse performance than a 6950 in Dirt 3 according to [H]'s benchmarks. Using the in-game benchmark tool, I was getting ~37 FPS average with the highest settings at 1920x1200, while [H] measured the 6950 at 40-something FPS. My CPU and RAM usage were not maxed out, though obviously my rig is less capable than the [H] testing one.

Think what I'll do now is grab a cheapish PSU at Fry's as a test and only hook it up to one of the cards, letting my Seasonic power the rest of the system. If that works, awesome, return the cheapie and nab an AX-850 or something.
 

CompMage

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550 Watts pull is very low. My AX850 Pulls about 700-725 on my APC when gaming using a pair of 6970s. While you have a slower CPU and not powering a water cooled rig you should be pulling something closer to 650 from that seasonic. I have noticed that most of the above games mentioned are memory hogs. You may wish to consider another 4g of ram.

Keep us posted
 

BababooeyHTJ

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The X750 in your sig should be more than enough. I had no issues with 6950 crossfire on a seasonic x650 gold.

550 Watts pull is very low. My AX850 Pulls about 700-725 on my APC when gaming using a pair of 6970s. While you have a slower CPU and not powering a water cooled rig you should be pulling something closer to 650 from that seasonic. I have noticed that most of the above games mentioned are memory hogs. You may wish to consider another 4g of ram.

Keep us posted

700w? That seems really high even my GTX570s in sli at 1.05v seemed to top out at around 650w. At stock speeds they top out at around 550w.
 

Starslayer67

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Alright, well, my idea didn't work. The card I connected to the second PSU got power I think, but it was not recognized by the system for some reason, and all that happened is the fan spun at 100%. I also have started to notice some checkerboarding in moving game images. I'm not sure if this due to the low framerates I'm getting or if it portends something more serious. In lieu of any other solutions, I'm going to go back to my old 460s for now.

I'm thinking about ordering an AX850 and another Crossfire bridge from Amazon just to test this again; I think now something is up with either my PSU or mobo, since I should be drawing much more power than I do at load. System idle in Crossfire is holding at ~300 W counting the monitors.

If that stuff doesn't work, what next? RMA the cards? Sell them (already tore off the UPC stickers for the MIR :()? I really can't think of anything else it could be.

P.S. Just to make sure I'm not being stupid, you only need one Crossfire bridge connected, right? I don't recall two making a difference anyway, but still...
 

tangoseal

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Not sure if this is a factor with your CPU but even if you have 8threads running is that CPU enough to feed those power hungry bastards of a card 6970's. I seen a noticable difference in throughput testing my I7 at stock speed then OC speeds.

And only one bridge is needed that is for sure! If it werent for sure then the 6990 would have came with 2 connectors and required you to use it.
 

Starslayer67

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Yeah, but they should at least be faster than my 460s. In single-card operation, they are, no question. But Crossfired, they don't come close to 460 SLI, when they should blow it out of the water. That's the problem here. My mobo can only do x8/x8 PCI-E, but given [H]'s benchmarks on the matter, I'm inclined to believe it really shouldn't be a big factor, and the symptoms don't seem to match that. If it is a large factor, well, I'll have to sell the cards, because I cannot afford to replace my mobo and CPU right now.
 

Jalidi

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I think your 750w Seasonic is plenty for Crossfire 6970's... for sure, my AX850 can totally do it, since I have a pair of 6970's too. Are you getting this same strange throttling in 3Dmark11 and Vantage? Since it sounds like you've tried pretty much everything, at this point I'd recommend that you reinstall Windows from scratch and see if that helps. Btw that second Crossfire bridge, well attaching it won't improve anything, and it shouldn't degrade performance either. But you only need one, the second is really intended for a third card in a Trifire setup. Personally I have both of them attached and everything seems fine.
 

Ludic

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Do you think a Corsair 650 in my sig is enough for Crossfire 6970? I'm only running one right now.
 

rangda

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Call of Pripyat.

You're not alone with bad crossfire performance in this game. Running the Sigerous mod 1.7 I get ~30fps using the DX9 render path with crossfire 6950's @2560 (mod crashes in dx10/11). Card usage is around 60% for each card. I've been wondering if they did something that broke CoP performance in recent drivers.

I don't have crossfire performance issues in any other game.
 

Sufu

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A 750w PSU is not enough to power two 6970s in crossfire. Simply put, your 12v rail will likely be shit at full load, and the cards will suffer. I think it just can't push enough amps, but I am not 100% sure. Of course depending on how much stuff you have running, your YMMV.

I had that problem with 2x MSI 6970s on a Corsair HX750w PSU. I upgraded to the Enermax MAX REVO (1350w) and have been good since. Though like others have mentioned, crossfire performance is also hit/miss depending on the game.

I tried out the 1kw Corsair PSU at first, but it lasted 3days then my PC would no longer turn on (after a BSOD and a cold boot). I should have heeded the bad reviews @ newegg.
 

Starslayer67

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That's what I was kind of thinking, but the X-750 can push 62 A over the 12 V rail, according to the datasheet, and as [H] found out in the review, it can be pushed harder than that without failing. If that still isn't enough, or the power's just bad quality, well, the AX-850 I'll be ordering this week should do the job, at least according to Jalidi's experience. The only stuff I have running off the PSU not listed in my sig is 3 HDDs (all 7200 RPM) and 2 DVD-RW drives.

I'll be gone for half of next week, but I'll let you guys know what happens after I get back and install the AX.
 

Sufu

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Hopefully it works out for you OP. 850 may or may not be enough depending on what else you are powering, and any OCs.

I have 6x 120mm fans, water pump, 4x hdd, 1 ssd, and other crap in there, with overclocked msi lightning and oc i7
 

Starslayer67

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Nope, no overclocking for me. Might do it with these cards eventually, but if the 850 works, I'll be replacing that again with a 1 kW or something before I attempt it. I don't ever plan on OCing my CPU or anything like that.

Thanks for the well wishes.
 

Starslayer67

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Motherfucker. I think I can safely say now that power is not the issue. The AX850 did jack-all for the problem; the second GPU still throttles, and changing graphics settings still has little effect on framerates. This means, I think, that it's either the mobo or some weird software issue.

Does anyone have any real idea of the what the hell else it could be? This is extremely frustrating, obviously, and the cards will be going up on sale here unless either the 11.7 drivers or something else fixes it. I've just about had it with this shit.
 

sirmonkey1985

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try overclocking your 860 to 3.6Ghz and see if it helps. its possible you are bottlenecking the cards. if it doesn't work then thats just one more thing to check off the list of what could be causing the problem.
 

BababooeyHTJ

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Motherfucker. I think I can safely say now that power is not the issue. The AX850 did jack-all for the problem; the second GPU still throttles, and changing graphics settings still has little effect on framerates. This means, I think, that it's either the mobo or some weird software issue.

Does anyone have any real idea of the what the hell else it could be? This is extremely frustrating, obviously, and the cards will be going up on sale here unless either the 11.7 drivers or something else fixes it. I've just about had it with this shit.

Oh, you need to select the other card in the cat control center to bump power tune up for the second card. I made the same mistake thinking that the one slide was for both cards and was seeing powertune kicking in and throttling the card in Metro. IDK, its worth a shot.
 

Starslayer67

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try overclocking your 860 to 3.6Ghz and see if it helps. its possible you are bottlenecking the cards. if it doesn't work then thats just one more thing to check off the list of what could be causing the problem.
I somehow doubt it will. I'm never hitting more than 75% utilization of any CPU core. In any case, is 3.6 GHz safe on the stock Intel cooler? I really can't afford to replace the CPU, mobo, or cooler at this time. Besides which, my 460s gave much better performance in both single and multi-display configurations, so I really doubt I'm bottlenecking them somehow, at least to the extent that I'm seeing. For reference, in DiRT 2 at 5760x1200, I get about 15-20 FPS on the 6970s with everything on low/very low, while the 460s pumped out 40-50 FPS with no AA and everything except post processing and SSAO on high/ultra.

BababooeyHTJ said:
Oh, you need to select the other card in the cat control center to bump power tune up for the second card. I made the same mistake thinking that the one slide was for both cards and was seeing powertune kicking in and throttling the card in Metro. IDK, its worth a shot.
Well, using powertune did cause the second card's usage to head up to 90-100%, but it didn't do anything about the framerates. I suppose it is possible that I got two bad bridges, but I'm not familiar with how a bad bridge would manifest.
 

sirmonkey1985

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I somehow doubt it will. I'm never hitting more than 75% utilization of any CPU core. In any case, is 3.6 GHz safe on the stock Intel cooler? I really can't afford to replace the CPU, mobo, or cooler at this time. Besides which, my 460s gave much better performance in both single and multi-display configurations, so I really doubt I'm bottlenecking them somehow, at least to the extent that I'm seeing. For reference, in DiRT 2 at 5760x1200, I get about 15-20 FPS on the 6970s with everything on low/very low, while the 460s pumped out 40-50 FPS with no AA and everything except post processing and SSAO on high/ultra.

Well, using powertune did cause the second card's usage to head up to 90-100%, but it didn't do anything about the framerates. I suppose it is possible that I got two bad bridges, but I'm not familiar with how a bad bridge would manifest.

just because the cpu usage never goes over 75% doesn't mean it isn't bottlenecking the cards.. for testing purposes the stock cooler should be fine at 3.6Ghz just run intel burn test for 5 passes and make sure the overclock is stable then test it out in a couple games. if the games work better then you may want to invest in a aftermarket heatsink like the cooler master hyper 212+ which can be found for 40 bucks or less if you look in the right places. well worth the investment in an aftermarket cooler anyways.

a few pointers:
your processor is good up to 100C at that point it will begin throttling until it hits 110C which at that point it will shut the system down.
also keep your cpu voltage under 1.5v, odds are you may not even have to raise the cpu voltage to hit 3.6Ghz do some searching before hand and look at some reviews of the i7 860 that have overclocking results most of them out there will have overclocking numbers with the stock cooler instead of an aftermarket cooler(or in the case of [H] who use water cooling).

since i have nothing better to do tonight i'll also search around because i'd like to see if its actually the cpu thats bottlenecking the cards myself as well.

heres some numbers i found with the i7 860 overclocking on the stock cooler..
http://www.anandtech.com/show/2839/8 (4Ghz @ 1.35v)
http://www.overclockers.com/forums/showpost.php?p=6283482&postcount=1 (3.6Ghz @ 1.072v) the more and more i read i'm doubting this overclock was even stable even though the person claims it was but it really comes down to what your processors vcore is since its different on every intel processor

obviously you don't need to go to 4Ghz and you definitely won't need that much voltage to hit 3.6Ghz, but at least you know it could do 4Ghz on the stock cooler. from the numbers i've seen it looks like 1.16-1.25v is about the average for 3.6Ghz.
 
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e-geek

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"A 750w PSU is not enough to power two 6970s in crossfire. Simply put, your 12v rail will likely be shit at full load, and the cards will suffer..."

It doesn't matter if you have a 650 or 750 as the amps on the 12v is what really counts for high end vid cards, i have a corsair 650 as well and full load with crossfire 6850's and PII X6 @ 3.9ghz wasn't near 80% usage.

I bet you it will run 2 x 6970's fine as when i bought it (modular version) i made sure it had enough amps on the 12v rails, m/b software shows 12v @ 12.04v under full load no issue here.
 

Starslayer67

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I threw the X-750 back in and OCed to CPU to 3.7 GHz (stable, though it throttled something fierce during the burn test), and there was no performance difference whatever. To my mind, that leaves the mobo or bad Crossfire bridges. Anyone think I should order another bridge to test?
 

sirmonkey1985

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you could try a new bridge and see, doubt it would be the motherboard but you can test each card without crossfire enabled and see if one of the slots are bad or maybe one of the cards are bad. sucks to see it wasn't an easy fix like just overclocking the processor. oh well it was worth a shot anyways.
 

Kor

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I don't think it's your cards, i'm pretty sure it's a driver issue when running eyefinity. I'm observing a similar issue in regards to GPU usage mismatch using crossfired 5870's, have been for a few months now. The problem is most apparent when using vsync, especially in DX10/11 titles. Under DX10/11 I've found that the whole screen checker boards in the even that the card that's being under utilized can't keep up with the full loaded card. I submitted a bug report to AMD a few months ago but they obviously don't want to acknowledge the problem.
 

shantd

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Right off the bat, based on your first post, this didn't strike me as a power issue and I was kind of surprised to see so many suggestions along those lines. You've tried 2 CF bridges already so I really doubt that's it, and it's most certainly not something that a little over-clocking is going to fix. For starters, 750w is a good amount of power. Besides that, and more importantly, an under-powered PSU wouldn't explain why your master GPU is at 60% while the slave GPU is stuck at 100% the whole time. That sounds like driver conflict to me.

If I had to render a guess, I'd figure you wouldn't be having this issue with another mobo/components. Kor may also be onto something above re: eyefinity. Also remember that 6970s are kinda prone to issues when crossfired in general. AMD has a long way to go with their drivers.

Have you checked around online to see if other people with your same mobo/components have had similar issues with 6970s crossfired?
 
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Starslayer67

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I did check around earlier on to see if people had issues with 6970's Crossfired, not just with my components; they did, but nothing with my symptoms, and the fixes I found didn't work IIRC. I shall check again.

It also is not just a problem with Eyefinity - Crossfire is providing little to no benefit in Eyefinity and single screen. The framerates in Eyefinity are 1/3 to 1/2.5 what they are in single screen mode. As I mentioned in one of my more recent posts, increasing the power available to the slave using Powertune in the CCC (I mixed up the master and slave GPUs in my first post, sorry) did bring its usage to 100%, but this had absolutely no effect on framerates.

I have tested each card in the primary slot, and each performed exactly the same; as I mentioned earlier, the FPS I got was worse than [H] obtained with a 6950, but it wasn't so bad as to suggest a faulty card or slot. I have not yet tested one card running alone in the second slot. I shall try that today.

If that doesn't tell me the problem, I will hold on to them until the 11.7's are released (I have that beta driver that got released, but haven't tried it yet), and try those. My housemate has my old system, which I suppose I could try the cards in (it's got an ASUS P5Q-E mobo), but if the age of the mobo is the factor here, I don't have high hopes.
 

Starslayer67

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Holy shit. I think it's probably a bad slot. I disconnected the top card (master) and just used the bottom one for video alone. Performance jumped by a factor of three. Dirt 2 hummed along 40-45 FPS with everything turned on at 5760x1200. I'm going to test a couple more games, then put the other card in the second slot just to see if it's bad (I don't think it is, but hey). I'll report back once I've done that as well as Crossfiring using the bottom card as the master.

Guess it's time to scrounge some money for a new mobo and CPU...

EDIT: Ok, tested everything in the preceding paragraphs. Almost certainly a bad slot: each card performs identically, but as soon as Crossfire is enabled, the top slotted card drags the other one down with it.
 
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sirmonkey1985

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did you test the bottom card in the top slot by its self as well just to double check or did you just run both cards in the bottom slot when testing them?
 

Ludic

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I would try resetting your motherboard BIOS... to optimal settings if you have that option. I spent four hours chasing ghosts last night trying to get my CrossfireX 6970s to work, and that ended up being the answer. I'd also double check to see if your motherboard requires extra PCIe power connectors. Mine did.
 

fanboy

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Even CX5850 on the x58 Intel platform with a i7-930 needs aleast the Corsair TX 950 watt powersupply for stable gaming.. also i found that when adding the 2nd card for CX ..reset my cmos helped alot as the DMI data pool picks the 2nd card up better.
 

shantd

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I'm glad you seem to have found the answer, though it sucks that it wasn't an easy fix afterall. Too late to rma your mobo, I assume?

As for the bad slot, just throwing this out there but if it was indeed bad, would it be performing at all? From what you've said, the slot does work on a diminished level but it would seem to me that if it was a bad slot, it wouldn't give you anything, would it?
 

shantd

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Can't hurt. Resetting the BIOS has helped me a few times over the years...on totally unrelated matters, granted. I think most all modern day bios' will have the 'optimal settings' option you mentioned.
 

Starslayer67

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K, I'll try resetting the BIOS. Certainly can't hurt. And extra PCI-E power connectors for the motherboard? Eh?

My thought on "bad slot" was that the mobo for whatever reason has throttled the slot, possibly because it had gone bad at some point. Now that I think more about it, though, it is most likely just something in the BIOS which would be doing that.
 

Starslayer67

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No dice. Clearing CMOS did not do anything for the problem. The bad performance using the top slot persists.
 

Ludic

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Did you double check for PCIe power connectors on the motherboard? I had two I hadn't seen before in separate spots.
 

Starslayer67

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My mobo has no such thing, after a visual inspection of the board and reading the manual to make double sure. And if power were any kind of issue, why would the second PCI-E slot be all fine and dandy, while the first (and only the first) is giving me trouble, even in single card mode, and regardless of whether Eyefinity is engaged? They'd be running of the power source, after all...
 
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