Hey guys - I have some issues with overclocking in SLi. I was aiming for 1500MHz GPU boost clock on both my GTX 980 cards but I'm no where near it. I used to have a single Asus GTX 980 STRIX and the max stable that card could run was 1330MHz base clock which translated into 1443Mhz boost clock (maxed voltage and power target). Any boost above 1450Mhz and the screen would go solid black/grey or maroon. Max on the Vram was 1950MHz. Later I had it running SLi with a Gigabyte GTX 980 G1 Gaming, and appearently the Gigabytes OC potiential looked limited by the Asus card. So I decided to replace the Asus card with an Inno3D GTX 980 Ichill HerculeZ X4 Air Boss Ultra card which I know is a good OC'er. So I put this card and the Gigabyte card in SLI and I hope to run 1500MHz+ boost now. I choose to de-sync OC, and OC each card with their own settings, since the base clocks on the two aren't the same Inno3D 1266mhz gpu and 1800mhz vram, Gigabyte 1228mhz GPU and 1753mhz vram. But no luck at all. Initially I had the large 3 slot Inno3D card on top giving about 2mm space between the cards. I experienced that above 1503MHz the I'd either get a black screen or den Nvidia driver crashed and recovered. In MSI Afterburner it was easy to spot which card triggered the crash, and it was always the settings for the Gigabyte card that would reset when chrashed. I cranked down a notch so both would run 1493MHz boost which I would accept. But as soon as I started with 3Dmark and 3Dmark11 I'd get either errors from 3Dmark or driver crashes at random. I then tried Unigine Valley 1.0 and Heaven 4.0 but halfway through the benchmarks I'd see the temperatures on the Inno3D hit 85~86°c and the boost would go down to 1455MHz, but the benchmarks ran fine. So I decided to swap the cards around putting the 3 slot inno3d at the bottom and the Gigabyte in top making about 2cm space between the cards. Switching the card around only helped temperature wise but not with overclocking. I maxed the voltage and power target for both cards, but running above 1470MHz boost clock the driver would reset randomly and sometimes crash to a black screen. So what I ended with was going back to the same OC settings I used to have with the Asus card with 1330MHz base clock and 1950mhz vram - then both cards would boost to 1468Mhz and everything seems stable, however when running Unigine Heaven 4.0 it drops down to 1455MHz. The Gigabyte card hits around 82°c at it's hottest in the benchmark, but setting the temp limit to 89°c doens't affect the boost speed, it will still rung at 1455MHz. I have power usage in MSI Afterburner enabled and the Gigabyte sits at a max 74% power usage and the Inno3D at 84%. But still it's the Gigabyte card that now limits the OC potential. "Sigh" - I've almost given up chasing 1500MHz boost clock in SLI, since I can't get a stable setting no matter what I do. But before throwing the towel in the ring I want to ask if any of you could help with some tweaking options that could make my cards run 1490 or close to 1500Mhz if possible. Also what OC setting are you 980 SLi user running at ? Oh yea I did try updating from Forceware 353.30 to 355.60 but no difference.
Most cards don't even do 1500 in single mode so hoping for that in 3 way SLI is rather optimistic. You'll just have to live with 1455. It'll be hard but time is good healer!
Have you tried finding your max overclock leaving the voltage at stock? Just maxing out the voltage doesn't necessarily result in the highest stable clock.
@ Gripen90 mine run similar temps, the topcard always run much hotter then the bottom, what are your asics on both cards ? With the standard temp-limit of 83 your card will not trottle or downclock until it reaches that temp, but another question why the hell did u bought 2 different brands ? Isnt that asking for more trouble ? If i were u i would return that inno 3d or the gigabyte and get the same 1 of the same brand.
Your videocards look a bit choked. Have you considered a PCIE extender and moving the lower gpu to a lower position? Room ambience and box ventilation play a huge role on OC.
You could have helped yourself and gotten two of the same brand, could have helped. Also, you're forgetting the SLI voltage bug. Your cards won't get the same voltage, thus probably not reaching the same max overclock you'd want to have for SLI stability. afaik the only way to handle this would be custom bios versions, different ones, on both cards.
Yea I did try that also individually but both cards need max voltage to keep a steady boost clock I am trying to see what max clock the Gigabyte card will do individually with different voltage settings. Because the GTX 980 cards were bought used to save cash (my 95% of my 2nd PC consists of used/2nd hand parts), I couldn't find any selling two Asus or Gigabyte cards at the time. So I bought one of each for SLI. Also I never has problems running different brands or speeds in SLI - it's just this time if would like to get 1500Mhz out of them - just for the sport of OC'ing. The weird part is that even with max power target and voltage the power usage never goes 100% on any card - max 74% on the Gigabyte (1.241v) and 84% (1.156v) on the Inno3D - the temperatures are well under the max limit, so can't really understand why I cannot pull any more out of the cards. There's fine ventilation in there (also 120mm side panel fans and a custom-made GPU cooling rack of 4x40mm fans that blow directed air in between the cards - I've had 2x MSI GTX 780Ti TwinFrozrs in there in SLi and they were hotter GPU's. As mentioned this PC consists of 90-95% used parts. At the time I couldn't fine any selling two identical GPU's. As for the SLi voltage bug I wasn't aware of. I'll have to look into it
Ah, my bad, didn't read the used parts thing. But yeah, google it ('sli voltage bug' already brings a few hits), and if you're patient enough, read through the Maxwell overclocking thread over at overclock.net, that's where I've read about custom bios and how it might help. If you're running an asynchronous overclock I'm not sure you need to worry about it though.
I'd put the card with the highest ASIC as the top card. If say GPU1 boosts to 1500 alone and GPU2 only boosts to 1450 alone then in SLI mode GPU1 will be forced to run at GPU2s speed (since it's the slower of the two). The benefit will be lower top card temp.
I did so intitially but it didn't have any affect as such - if there was it was only marginal. I am running a sync overclocking I read a bit about the different voltages and I recall them being different. One about 1.24 and the other 1.17 or so. I read about using NVINSPECTOR to adjust this difference which should give more stability and OC options. "Possible Fix: "I'm the one who created the thread in EVGA's forums, though I do have sli gigabyte 970 G1's I found a fix for it Use NVINSPECTOR program to adjust cards individual. It will take some testing, but I can get my primary card to get over 1.175vcore, it now can hit 1.243vcore. gpu-0 = +108mhz core, +320 mhz memory, MAX everything else gpu-1 = +148mhz core, +320 mhz memory, MAX everything else gets me 1.243vcore on gpu1 and 1.250vcore on gpu2 yielding a stable 1525mhz Before using MSI afterburner at +130mhz and +max voltage I was only getting 1.175vcore from the primary card at 1505mhz and any bump of mhz was keeping it at 1.175vcore, causing lockups." Any how I am getting a MSI GTX 980 Gaming 4G now I will pair with the Inno3D card and see how the OC goes - and I'll try the above trick (sold the Gigabyte).
