I'm really happy about the new fglrx drivers and that my new Radeon HD 2900Pro works well in Linux. But yesterday I thought I should test my system's power consumption, because in Linux I can hear the cooler of the video card more often and running a lot faster/louder than in windows.
There, the card clocks down when in 2D mode, and higher in 3D mode. Thus, the power consumtion is about 180W in idle and up to 300W during a game (overclocked to XT). Which is high, but I can live with that, cause I'm not playing all the time and in 2D mode I can undervolt the card so that the whole system needs only about 160W when idle. Undervolted or not, in windows the cooler is never hearable. But in Linux it's loud all the time and the electric meter confirms this: 230W when idle with 2900XT firmware and (what I do understand even less) with 2900Pro firmware, where the clock should be lower, it drags even 250W. 70W more than in Windows! Disabling AIGLX and Composite effects doesn't help, PowerPlay isn't available because of the driver or because the card doesn't support it. Thus atipower shouldn't work and rovclock hasn't any support for newer cards yet (saying "invalid reference clock from bios").
So my question is: will there be a way to lower the gpu clock in the near future, e.g. with new fglrx drivers, better support in radeonhd drivers and/or tools like atipower and rovclock? For me, 3D in Linux isn't a must-have, because I'm using Windows for playing (and only for this) and "unfortunately" most of the time Linux for "working", where I could live without compiz. If only I could underclock this card. 70W is a lot when the computer runs at least half day, at least in Germany for a poor student
Otherwise I have to take a closer look at the next 8800gt tests and consider selling my 2900pro. Perhaps this works better on nvidia's side? (though atm ati drivers make huge progresses!)
I'd be happy if anyone has information about this issue!
aticonfig --lsp says
"Error: POWERplay is not supported on your hardware."
Perhaps it will be in fglrx 8.69.3 or so, or, if this is really a hardware thing, it will never be supported by ati drivers.
But at least after I disabled Compiz/AIGLX/Composite and did a reboot (last time a X-reboot didn't suffice), it consumes only 180W, as much as in Windows Vista in 2d mode. When gaming it needs more, and it goes down again afterwards. I think I can live with that, that is 'til my next graphics card buy
Only gnome without compiz now seems a bit impractical to me, might switch back to e17 or the like...
I am having a similar issue with x1650pro using latest driver. I guess now that 3D is working the GPU is getting hotter so the fan is running faster. As soon as I downgrade the driver, the fan speed goes back to normal, or at least fluctuates as and when needed rather than full-on all the time as it is now.
aticonfig --lsp only offers one power state.
Still, this is one step forward and two steps back, having upgraded from a very satisfactory SuSE 10.2 to 10.3 I'm closer to getting what I want but at the expense of stability or usability again thanks to Ati drivers (1680 x 1050 with Compiz on a Ati x1650Pro is like being back in Windows when VL bus cards started to appear and I was still running my trusty Trident).