[FIXED] Radeon 6990M core clock stuck at 100MHz

I had a problem with the core clock on my 6990M staying at 100MHz, never increasing to the rated 715MHz, even when the temps were low and the card was being utilized at 100% by various games. As you can imagine, this caused performance to be much lower than expected. I'm posting the solution here in the hopes that if someone else has the problem, they can save some time by following the steps I took.

Some background: I was getting framerates of 6 to 8 when playing Skyrim on High settings (the setting that Skyrim picked). GPU-Z showed that the core clock stayed at 100MHz at all times. Temps were low.

I called Alienware support. The person I spoke with took over, and downloaded and installed the Heaven DX11 Benchmark. It showed the same low framerates, and GPU-Z showed that while the benchmark was running, the clock never changed from 100MHz. He uninstalled the driver I had in place (I had put the 12.x driver on) and put the original one from Dell back in place. That didn't fix it. He tried switching back and forth between the intel gpu and the 6990M, and that didn't fix it. Finally, he said that he'd like to reinstall windows, and if that didn't fix it, then it was probably a hardware thing. I asked that we do that in two weeks, and so we made an appointment for then.

In the meantime, I continued to do some research. I read about AMD Overdrive, which lets you set the clock of your card. However, AMD Overdrive wasn't present when I brought up Catalyst Control Center. I read how to cause Overdrive to show up: http://forum.notebookreview.com/alienware-m17x/616341-cant-find-atioverdrive-6990m.html#post7975117. Overdrive showed that the max clock was indeed set to 715MHz. For some reason, that setting wasn't taking effect. I then read about a person with a 6970 in a Sagar that appeared to have a similar problem: http://forum.notebookreview.com/sag...50-ati-6970m-gpu-clock-stuck.html#post8183454 . He changed the clocks to slightly different values, and that fixed the problem. I set my clocks to slightly different values as well, and that fixed the problem for me as well. I then set the clocks back to their original settings, and the problem did not return. I started skyrim up, it automatically selected Ultra settings, and now I'm getting great framerates.

 

David - this is a good discovery on your part. I had posted a similar finding on the M18x with 6970M CrossFire probably 5 or 6 months ago, so it's unlikely you would have ever found it. Nobody seemed to pay any attention to it at the time. I discovered it by accident experimenting with my cards to try to get them to work while waiting for back-ordered replacement video cards. (They were being replaced under warranty because of the same problem.) What I ended up doing (and it worked extremely well) was set all power states at the factory maximum default clock speeds. It prevented the AMD PowerPlay from slowing the cards down to conserve energy and that made the 6970M CF setup perform flawlessly. When I received replacement cards, they had exactly the same problem and I ended up doing the same thing to them to force them into behaving properly.

I've had nearly the same problem with the 5870 CrossFire on the M17x R2 and this trick works well there also. One or both of the cards would sometimes stay at 100MHz under load. I'm not sure why the AMD cards get stuck sometimes. It's an odd thing. Using the AMD GPU Clock Tool with the 5870 always seemed to get it "unstuck" for me.

 

I got quite same problem. If you deselect powerplay from ccc, your card stuck at 100mhz. Re enabling powerplay solved the issue.

 

Ultimately, I think the problem is PowerPlay related, but disabling/re-enabling it did not consistently work to correct this problem in my case. This would definitely be something David could try on the chance it will work for him. If it does work, chances are that the fix is temporary and the problem may resurface later. This could be a driver related bug, which would come as no surprise with AMD video drivers. But, changing the clock speeds worked 100% of the time for me. Doing so defeats PowerPlay, especially if you change the clock speeds to all power states in the vBIOS.

 

I had the same problem last summer when I got my used Eurocom Racer. Intel 2720 and HD6970M video. Damn clock was stuck at 100 also. I also tweaked the overclocking [Overdrive] just a nudge was all it took and presto, the cards took normal clock speeds and never had the problem again. The laptop had two previous owners, but it was only like 3 months old when I got it. Not sure if thats why the other partys sold it or not. Its fixed now and running perfectly.