How to disable Hyper-Threading in MacOS
Unlike their PC counterparts, Macs do not omit CPU settings such as Hyper-Threading in the EFI interface (well, except Hackintoshes). The process of disabling Hyper-Threading (aka enable "complete reduction for MDS") therefore requires some work in the Terminal.
After installing macOS Mojave 10.14.5 or the standalone security updates for the Sierra and High Sierra, do the following:
- Restore your Mac in Recovery Mode (hold Command-R) at startup .
- When the recovery interface loads, select Tools> Terminal from the menu bar at the top of the screen.
- Enter the following commands one at a time:
nvram boot-args = "cwae = 2"
nvram SMTDisable =% 01
- Restart Mac.
To enable Hyper-Threading later, reset the Macron's NVRAM by holding the keys Option + Command + P + R at startup for the Mac is restarted. Users can verify the status of Hyper-Threading by selecting Apple Menu> About This Mac> System Report . In the hardware section of the system report, an entry indicates whether Hyper-Threading is enabled or disabled on your Mac.