kacpi_notify eating processor; tied to monitor resolution?

After upgrading from 10.04 to 10.10, my Dell pavilion 542x runs very slowly and system monitor show much activity attributable to kacpi_notify. As I recall, I had the same problem in 10.04 but fixed it by modifying GRUB to turn acpi off. However, when I tried this in 10.10 it did shut off kacpi_notify as expected but fouled up my display.

I am using a flatscreen that likes to see 1680x1050 resolution. Works OK without the "acpi=off" in GRUB but when I add that parameter the system will not allow that resolution. So I guess I either need a better fix for the acpi problem or some insight as to how I can get the system to play better with the flatscreen.

Thanks --