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Radeon Driver Power Management Has Room For Improvement
I had also the same experience of slow switching between profiles with dynpm, and sync in blancing period is off when in low profile.
Dynpm does not switch between profiles.
You have to switch between profiles manually.
What dynpm does is it adjusts the clocks and voltages on the fly, trying to exactly match the expected workload. It does not switch between predefined profiles. This means that it's more flexible, but also far harder to implement.
The article has a funny title. "Room for improvement". lol. Seeing the performance and power consumption charts, the only conclusion is: the open drivers totally suck ass.
Frankly, after having read the article, what I took away was that power management was actually pretty good. Performance needs (lots of) work, but that's no surprise and that's being worked on everyday.
Also, IIRC a mesa developer said that normally there is a programmable power management module that isn't used in radeon atm, so all things considered, congrats mesa-devs
I've been giving the open driver an extended try for the past few days on my 5770 for the first time. My results are nearly identical to these results for the 5750 except that not only does dynpm not adjust itself properly (keeping itself never lower than the same frequencies of the mid profile) but it also creates very noticeable blinking of the screen whenever it does switch. I keep it in the mid profile mostly, which is just fine for everything short of playing games, or other significant 3d rendering. I just wanted to point out, however, that using this driver is a far better experience than catalyst for, again, everything other than gaming. I can actually scroll on chromium with it maximized with out any lagging (more than I can say for the catalyst driver with tear free on) or tearing (again more than I can say for catalyst). All video playback is perfect as well. I seriously hope someone works on getting dynpm to a useful state soon, because as soon as that works, without question I prefer the open drivers after using them a few days. The only bother I have is using the mid profile keeps me at a steady 55C, which isn't awful, but the fan noise really does kill me. Thats compared to somewhere in the mid 40's while using catalyst....Also unity and the new compiz in natty work much much better on the open stack. Using catalyst gives a much more jerky experience, plus the mouse corner lag bug in 11.5, and 11.6
I'm curious now what effect the different power levels have on the desktop? (e.g. Gnome shell). I rarely ever run 3d games so I don't need that much horsepower, just enough to composite my desktop smoothly. Curious now whether running low power mode is enough.
The other thing I find bizzar is that according to the DRM, my card doesn't have a low profile (or at least, it's the same as mid) but according to the benchmarks (comparing voltage) it's the mid profile that my card is lacking.
Being on a laptop, these things have increased importance.