Very bad performance with nvidia-driver

[Ivan Voras]

Hello,

I'm reinstalling my desktop after a hardware upgrade and I'm having 
problems with the nvidia driver (x11/nvidia-driver).

In short: it's horribly slow with desktop effects / compositing. I have 
enabled the FPS display and it cannot get to 60 even on an empty 
desktop. All operations requiring window redraws reduce the frame rate 
to a slide show (less than 5 FPS, many black lines in the FPS status 
display). 3D desktop cube rotates relatively smoothly unless there are 
windows to be drawn on the rotating desktops, at which point it's a 
slide show. I've tried playing movies with vlc player and it went fine, 
but watching youtube in the flash player in firefox again gives terrible 
performance and once even a hardware lockup.

This is relatively recent nvidia GT 440 hardware; before it I had radeon 
3600 (ancient), which had visual artifacts with the open source drivers 
but had acceptable performance.

I'm dual-booting this with Windows 7 where, of course, there are no 
visual performance problems at all, even with demanding games.

Any ideas?

My xorg.conf was generated by nvidia-xconfig; it looks very plain, 
without loading any modules or extensions except the "nvidia" driver in 
the "Device" section.

This is 8-stable amd64.