How to disable speedstep?

I'm using Clover and iMac15,2 SMBIOS. My CPU is 4790K. I have EIST and C1E disabled in BIOS, and Generate PStates set to false in the Clover config. In OS X the CPU frequency still bounces between 800, 4000, and 4400 MHz (multipliers 8, 40, 44). How do I completely disable SpeedStep to let the CPU remain at highest frequency?

iHackMyStuff said:

I'm using Clover and iMac15,2 SMBIOS. My CPU is 4790K. I have EIST and C1E disabled in BIOS, and Generate PStates set to false in the Clover config. In OS X the CPU frequency still bounces between 800, 4000, and 4400 MHz (multipliers 8, 40, 44). How do I completely disable SpeedStep to let the CPU remain at highest frequency?

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Sir, how did you enable speedstep? We have the same processor but I have the Z97 gaming 7 and I can't find a way, mine is always running at 4.4 Ghz.

Thank you.

Hi all! I am having exactly same issue as iHackMyStuff. Null CPU kext is not the answer here since our hardware running the newer versions of OSX uses a newer kind of power management residing in the kernel. Ive come across some info about a script that to my understanding can generate p-states for this new environment, it is Piker Alphas ssdtPRGen.sh script.

I just dont know what flag to use when i run the script. Lets say i would like to try two different set-ups in two different ssdt´s. What flags should i use to compile files for the following scenarios:

One that ONLY run my cpu in my highest overclocking state (say x47 multiplier).


One that consists of the lowest idle state(x8 multiplier) and directly switches to the highest turbo with no p-states in between. 2 states, idle and full power.


Please help with this, im so close to finally getting this computer up and running tailored to my needs!


P.s. is the -x 0 flag an option? It is supposed to disable xcpm power management? D.s.

Bump. I'd also love to disable speedstep since it puts the CPU to too low speeds when I actually am doing something like drawing in photoshop! 0.8-2Ghz isn't nice when I want 4.4Ghz then

iHackMyStuff said:

How do I completely disable SpeedStep to let the CPU remain at highest frequency?

Click to expand...

No native SpeedStep on non native hardware. SpeedStep is disabled as it was never enabled. Most OS X/CPU frequency tools do not report correctly with Ivy Bridge/Haswell and newer processors. Try Intel® Power Gadget, attach screenshot.

I have the same issue. Need to disable speedstep for stable maximum performance with the software I am using. Yosemite seems to ignore the settings in my bios (which has speedstep disabled).

The performance visible drops whenever Yosemite seems to think it can lower the cpu clockrate, so it's not just a faulty reporting (it's an older Core2 Quad Q6600 processor anyways).

yep, I have the same issue. my 4790K will go up to 4.7, if I stress Logic with enough plugins it will go all the way up to 4.7, but it is dynamic and bounces up and down.

With Windows I could override core parking and speed step with a registry tweak, plus power management settings and associate this with different power management profiles. Does anyone know if this is configurable on the fly or is this going to require an SSDT swap plus reboot?

https://clover-wiki.zetam.org/Configuration/CPU#cpu_latency
"The critical value is 0x3E8(1000). A lower value will allow SpeedStep, a higher one will not allow it."

Hi there,

It doesn't resolve anything, does anyone has a fix for that or I will have to keep digging for an answer that doesn't involve creating my own SSDT?