Better Power Management on GhostBSD with Modern Intel CPUs (8th Gen and Later)
If you're using GhostBSD on a modern Intel system (8th generation or newer), the default power management setup may leave performance states underutilized and idle power consumption high.
Avoid using powerd, as it does not support Intel Speed Shift (HWP). Instead, GhostBSD users should use hwpstate_intel, configure deep C-states, and adjust idle behavior for better efficiency.
1. Use hwpstate_intel, Not powerd
Disable powerd:
sudo sysrc powerd_enable=NO
2. Enable Deep C-States
Set the system to allow the deepest available C-state: sudo sysctl hw.acpi.cpu.cx_lowest=Cmax
Persist this setting: echo 'hw.acpi.cpu.cx_lowest=Cmax' | sudo tee -a /etc/sysctl.conf
To see how well your CPU enters sleep states: sysctl dev.cpu.0.cx_usage
Look for non-zero usage of C3, C6, or C8.
3. Set the Optimal Idle Handler
GhostBSD supports several idle mechanisms. Check available ones: sysctl machdep.idle_available
Typical output: machdep.idle_available: spin, mwait, hlt, acpi
Use mwait for best compatibility with modern Intel CPUs: sudo sysctl machdep.idle=mwait
To make it permanent: echo 'machdep.idle=mwait' | sudo tee -a /etc/sysctl.conf
If mwait causes instability, try hlt or fall back to acpi.
4. USB Devices and Idle State Blocking
Some users wonder if USB activity prevents deep sleep states.
On GhostBSD, the hw.usb.no_poll sysctl is not available. However, you can check USB interrupt activity with:
vmstat -i | grep usb
If this command returns nothing (as it does for many GhostBSD users), USB is not interfering with C-states. There is no need for further USB tuning.
5. BIOS/UEFI Setup Checklist
Make sure the following options are configured in firmware:
Intel Speed Shift (HWP): Enabled
CPU C-States: Enabled
C1E: Disabled (optional, may improve deeper sleep)
Legacy CPU power features: Disabled if present
Reference Links
Archived guide from Neel Chauhan:
https://web.archive.org/web/20250315073729/https://www.neelc.org/2022/03/10/optimizing-freebsd-power-consumption-on-modern-intel-laptops/
Discussion thread:
https://forums.freebsd.org/threads/freebsd-uses-a-lot-more-power-in-desktop-also-wont-go-into-c-states.97069/
