Powertune confusion

[Ruahrc]

Pretty new to modern video cards, as I have a new build from about 2-3 months ago which is the first I have made in >5 years.

I'm using the MSI 6950 2GB Twin Frozr III (factory overclocked version). It's inside an SFF case on a mITX mobo.

Anyway, I'm trying to figure out if I can optimize my system further using the powertune slider in the CCC? But I'm not really understanding what it is supposed to do, and where/when it will benefit.

As I understand it, powertune merely raises the TDP barrier that your GPU is allowed to run at? So if the default is say 250W, but setting powertune to +20 will raise it up to 280W or something?

But, if your GPU never hits the TDP limit, there will be no benefit in performance. However, at the same time- if your GPU is never hitting the TDP limit, there also is no "penalty" for setting powertune +20% either, right? Because it was never throttling the GPU anyways?

I have MSI afterburner running on my system and have over the past few months been monitoring my GPU temps/behavior as I have played games. I can't recall a time where I have seen the GPU clock down in order to lower its TDP. It always reports solid 850MHz when gaming, and something like 350MHz when at the Windows desktop. However, I only set my polling interval in MSI Afterburner to 5 seconds to see a longer total history, so maybe I just don't have the granularity to see the throttling behavior (since it supposedly operates on a frame-by-frame basis?)

My temps are pretty low, and recently I have even undervolted the GPU slightly to get it to operate cooler/quieter. In the undervolted state, running simultaneous furmark and Prime95 results in my GPU and CPU being at 70C. Playing Star Trek Online (which seems to heat my GPU more than any other game I have) the GPU temps are around 65C. That's about a 3-4C improvement over what I was getting in the stock voltage state (which the MSI factory overclocked cards have slightly boosted voltage over the reference chips).

Basically I'm asking whether or not setting the powertune slider to +20 will improve things any, or since I don't seem to be hitting the TDP (nor is my card running that hot), my GPU is running at maximum clocks all the time already? The one thing that gives me pause is that when I was doing my voltage tweaking, I noticed that I could run prime95 and furmark simultaneously and could operate stably at 1.045V GPU. However, this caused frequent driver crashes in Star Trek Online, where the game would not crash but there would be a long hang and then things would move again, and if I checked MSI afterburner it showed that the voltage had been restored to the default values. I had to raise my GPU voltage to 1.070V in order to get STO to run stably. So despite the higher temps, it seems like furmark was less dependent on GPU voltage? I thought then that maybe STO was actually pushing the GPU harder than furmark (wouldn't be surprised, since it seems to be coded like shit), and that maybe powertune could address this?

Thanks

Ruahrc

 

[PersonalJ]

If you aren't hitting the tdp limit it won't make a difference, mine hits the limit in furmark and requires powertune to be set to +20%. It sounds like your overclock wasn't stable on that low voltage and when the driver resets itself, it will revert to the stock settings of the card. Hence why MSI afterburner showed the default values. Powertune shouldn't address that, but I'd set it anyways.

It sounds like you're not actually monitoring the GPU clocks, you'll want to use GPU-Z to see what is truly going on, afterburner and AMD overdrive will not report present clocks and will not show throttling.

 

[Ruahrc]

Yep you were right. I looked in GPU-Z and sure enough my card was throttling during Furmark. I upped the powertune to +20 and oh man the heat! My GPU temps jumped from 70C in Furmark up to 77-78C. But OTOH I was getting about 25% (!) increase in FPS as well (from 14-15 to about 19, when running at 1920x1080 and 4xMSAA). Obviously an extreme case but I guess there is performance gains to be had when maxing the TDP with powertune. Fortunately I was still able to use the slightly undervolted 1.070V for the GPU and get stable tests in Furmark.

I did some testing in Star Trek Online and found that even with powertune set to zero, the GPU never throttled. So in the end no real difference as far as gaming temps or noise, at least in STO. But I have left powertune on +20 in case a game needs the extra oomph.

Thinking about it more, this probably explains why STO was more stringent with voltages than Furmark was before. Since furmark was throttling the GPU back to the 600-650MHz range, it could run more stably with the lowered voltage as compared to STO which was running at full clock (850MHz) all the time. Now that powertune won't throttle Furmark, it also needed the higher 1.070V to run stably as well.

Running full-tilt (fan speed about 52%), this Twin Frozr III card is actually kinda loud. I think I might tweak my cooling setup slightly to try and give it better ventilation. I think definitely it is being starved for air slightly in my small case since the GPU temperature can easily influence the CPU temperature, and the case ambient temp rises somewhat when the GPU is under full load. I have my case fans set pretty aggressively towards quiet (Noctuas with the blue ULNAs) maybe I'll swap a couple of them for the black LNAs instead, to help get more cool air in the case.

My friend recently built a computer with an EVGA GTX580. The cooler design is pretty standard, the same type as the ATI reference cooling. I would have imagined that fan would be pretty loud, but we loaded Furmark on his build and his GPU fan was much quieter than mine! Granted his card sits in a full tower case with much better ventilation, but I was surprised at how quiet that design was, especially for a card with supposedly much higher TDP than the 6950 and, supposedly, an inferior cooler.


BTW MSI afterburner actually does accurately track GPU clock too, just have to scroll the monitoring graph down (or rearrange the default order of graphs). I guess I was looking at something else or remembering wrong.

 

[PersonalJ]

Yep you were right. I looked in GPU-Z and sure enough my card was throttling during Furmark. I upped the powertune to +20 and oh man the heat! My GPU temps jumped from 70C in Furmark up to 77-78C. But OTOH I was getting about 25% (!) increase in FPS as well (from 14-15 to about 19, when running at 1920x1080 and 4xMSAA). Obviously an extreme case but I guess there is performance gains to be had when maxing the TDP with powertune. Fortunately I was still able to use the slightly undervolted 1.070V for the GPU and get stable tests in Furmark.

I did some testing in Star Trek Online and found that even with powertune set to zero, the GPU never throttled. So in the end no real difference as far as gaming temps or noise, at least in STO. But I have left powertune on +20 in case a game needs the extra oomph.

Thinking about it more, this probably explains why STO was more stringent with voltages than Furmark was before. Since furmark was throttling the GPU back to the 600-650MHz range, it could run more stably with the lowered voltage as compared to STO which was running at full clock (850MHz) all the time. Now that powertune won't throttle Furmark, it also needed the higher 1.070V to run stably as well.

Running full-tilt (fan speed about 52%), this Twin Frozr III card is actually kinda loud. I think I might tweak my cooling setup slightly to try and give it better ventilation. I think definitely it is being starved for air slightly in my small case since the GPU temperature can easily influence the CPU temperature, and the case ambient temp rises somewhat when the GPU is under full load. I have my case fans set pretty aggressively towards quiet (Noctuas with the blue ULNAs) maybe I'll swap a couple of them for the black LNAs instead, to help get more cool air in the case.

My friend recently built a computer with an EVGA GTX580. The cooler design is pretty standard, the same type as the ATI reference cooling. I would have imagined that fan would be pretty loud, but we loaded Furmark on his build and his GPU fan was much quieter than mine! Granted his card sits in a full tower case with much better ventilation, but I was surprised at how quiet that design was, especially for a card with supposedly much higher TDP than the 6950 and, supposedly, an inferior cooler.


BTW MSI afterburner actually does accurately track GPU clock too, just have to scroll the monitoring graph down (or rearrange the default order of graphs). I guess I was looking at something else or remembering wrong.

My powercolor has dual fans and at 100% fan speed only hits like 67 degrees Celsius while under 100% gpu load with a much higher overclock and voltage. Set up a custom fan profile in MSI Afterburner.

 

[Ruahrc]

I do have a custom fan profile set, I turned it down to make it quieter, at the expense of a little heat. Basically a linear ramp starting from 25% at 40C up to 55% at 80C. Beyond 80C it aggressively ramps up the fan speed (I think it hits 100% at 85 or 90C) in case of a runaway thermal situation.

With this profile, it seems to run at about 60C under gaming loads, which is plenty acceptable for me. I knowingly run it a little hot (at least hotter than it needs to be) in trade for quiet. 100% fans on this thing is super loud.

I removed the mesh grille that covered my top 120mm exhaust fan and I think that helped too, since it seems to blow significantly more hot air out the top now that there is no restriction to the airflow.