View Full Version : Disable Hyper-Threading Mountain Lion 10.8 (Speed Up the Mac)

Dec 10, 2012, 10:32 PM
I would like to disable HT from my MacBook Pro Retina running on 10.8 (Mountain Lion)

I found some solutions on the Internet but they don't work or not enough for me :eek:

On 10.7 (Lion) this solution works fine but doesn't on 10.8
OFF: sudo nvram SMT=0
ON: sudo nvram -d SMT

The second works on Mountain Lion but it's not permanent.
Install Xcode->Open Instrument App->Preferences->Disable Hardware Multi-Threading.
It's not permanent unfortunately, after restating the Mac everything returns to normal.

The last one (Last Hope :rolleyes: ) works but.....
sudo nvram boot-args="cpus=4"

This solution gave me 4 Cores at Activity Monitor (But I'm not sure if it's 2 Cores + 2 Threads or 4 Cores + 0 Threads)
I beleive it's 2 Cores + 2 Threads because I felt the Mac little bit Slow.

Now I'm looking for a permanent deactivation of HyperThreading on Mountain Lion.
Help Please???? :(

Edit: Why Disable HT From 10.8 ?
When I disabled HT with Xcode Instrument, my Mac became tooo fast, all applications started fastly even Apple Video Editing apps like iMove and Final Cut Pro.

Why permanent ?
For Bootcamp Windows 7.
I tried Assassin's Creed 3, works fine on rMBP but when I checked Ubisoft Forums, some users said that HT slow down games, also Ubisoft Recommend to disable HT.

Dec 11, 2012, 01:36 AM
So, did you run some proper benchmark? Because applications are cached on the ram after the first time you launch them.

Dec 11, 2012, 08:32 AM
I know Ritsuka
I did the test before the applications are cached on RAM. (restarting Mac)
Try it by yourself, open Final Cut Pro or a 3D Application Like Autodesk Maya and start Rendering, you'll feel the difference.

Do you have any solution to disable permanently HT on 10.8?