How to enable C2/C3 state to save power?

npforce

Hi, I'm new to NetBSD and wonder how I can enable C2 or C3 states to save power? I'm using it on a T420 laptop and observe the cpu stays in C1 despite no workload. Kill-a-watt shows a power draw of 20W. On FreeBSD I was able to see the cpu go into C2 and thus reduce the power draw to 10W. On Linux it can go into C3 and reach 8W.

thanks!

rvp

npforce Looks like the lowest you can go on x86 right now is C1. See if estd helps--though I'm not sure how useful it is on newer x86 CPUs.

npforce

Thanks. I’ll give estd a try.

rvp

npforce OK. BTW, FreeBSD goes to C3 too if you run on battery power.