I tried -cclock,  but it didn’t seem to have any effect on Radeon R9 290X. I also tried to  write to /sys/class/drm/card0/device/pp_sclk_od, according to this

https://www.phoronix.com/scan.php?page=article&item=amd-rx480-od&num=1

but the value didn’t change from zero.

Is there a way to overclock Radeon R9 290X in Claymore? I’m using AMDGPU-Pro Driver 17.40