This happens to me with the nvidia, the nv, and the nouveau driver.
Here's another thing I noticed: when I have the issue, xorg is not able to open the acpid socket:
(WW) Open ACPI failed (/var/run/acpid.socket) (No such file or directory)
If I log out and log back in, things go back to normal:
(II) Open ACPI successful (/var/run/acpid.socket) and cpu usage is normal.
This happens to me with the nvidia, the nv, and the nouveau driver.
Here's another thing I noticed: when I have the issue, xorg is not able to open the acpid socket:
(WW) Open ACPI failed (/var/run/ acpid.socket) (No such file or directory)
If I log out and log back in, things go back to normal:
(II) Open ACPI successful (/var/run/ acpid.socket) and cpu usage is normal.