Performance 3D mode is selected if an external monitor is attached

[SiggiUA]

I am using Vista X64 on a Dell M4400, FX 770M.

It is very easy to reproduce my problem.

1. Download GPU-Z to measure the clock frequencies

http://www.techpowerup.com/gpuz/

2. Start GPU-Z on an idle desktop with no external monitor connected. The GPU clock is 169/100MHz.

3. Connect an external monitor (idle desktop). Immediately the clock frequency will be increased to 800/500MHz and remain at this level all the time.

The graphic driver switched to 3D performance mode even though no 3D application is running. How can I avoid this false 3D detection?

I downloaded new drivers from laptopvideo2go, but the situation did not change. Unfortunately there is no configuration setting on the UI for the manipulation the clock frequency. Rivatuner does not recognize my card, other tools do not run under Vista X64. Only with powerstrip I was able to manipulate the frequencies down to 334/250 MHz (but only after I changed the registry entry PowerMizerLevelAC from 1 to 3). This is better than nothing, but the system is still louder as before with the 169/100 MHz 2D clock.

Any help would be greatly appreciated.

Edited February 11, 2009 by SiggiUA

[Phnx]

Unfortunately, this is the same with all nvidia GPU's, as soon as it renders to 2 screens, it jumps to 3d mode. As far as I know there is no way to disable it. If anyone knows a way, I'd love to know too.

Edited February 10, 2009 by Phnx

[SiggiUA]

Thank's for the reply. Is there at least a tool with what I can force the FX770M to operate in 2D mode? Rivatuner does not recognize my card and the low level settings are not available.

I also tried the Nvidia "System Tools with ESA Support". Nice user interface, a lot of performance settings, but unfortunately all controls have no effect on the actual frequencies. Am I too stupid or are the system tools not working with the Dell driver?

Edited February 11, 2009 by SiggiUA

[SiggiUA]

I made a lot of experiments, if someone is interested in the results:

I could not solve the problem, but at least the system is most of time quite if an external monitor is attached.

Edited February 12, 2009 by SiggiUA