I am in sarge, with a s3 savage 3d card. I have the same flicker problem with debian package.
I found out that XFree86 4.3.0 official (unpatched) binaries, which include savage driver version 1.1.20 work well. I can even start X with Debian driver (flickering), then change savage_drv.o from debian to Xfree's one, then start another X session in :1, then kill the session in :1, restore original savage_drv.o, then switch to :0 and the flickering disappears completely. From now until i reboot the machine there will be no flicker, even if i restart X debian version again. I also have problems with debian driver when trying to set up 16-bit mode (the monitor complais about extreme high frequency 160Hz, but XF86Config-4 should prevent it to go avobe 90 Hz).
