This is a Dell D630 laptop running Ubuntu 9.04 with the updated nvidia drivers from http://ppa.launchpad.net/ubuntu-x-swat/x-updates/ubuntu
CPU usage is relatively high even when idle (Xorg at 15%) but load average is even higher. Values are always above 2, averaging to 2.63 with just firefox and this post open. Thermal monitor says GPU temperature is 74 C, which I believe is too high for an idle system without desktop effects enabled. Fans are running constantly.
Performance of the system is slightly degraded, but well usable, except for the fan noise.
In Ubuntu 8.10 it behaved nicely.