This message was posted on behalf of Intel Corporation
Thank you for joining the Processors Community. I am sorry to hear you are having issues with the frequency.
It behavior seems related to the update itself, this since you are able to get faster speeds in the BIOS . I believe that some components were not fully updated with the update, so let's try updating the following:
- Intel INF installation: http://download.gigabyte.us/FileList/Driver/mb_driver_chipset_intel_rs3.zip
- Intel Management Engine Interface: http://download.gigabyte.us/FileList/Driver/mb_driver_intel_me_rs3.zip
Thanks for the assistance.
Turns out the issue is to do with a Gigabyte software called 'Easytune' that I have previously installed. Before uninstalling it, it might have been set to 'Eco' mode, and as such, was limiting the clock speed to 3.6GHz. I re-installed the software just now, changed the setting to 'Default' and I'm getting the full 4.2GHz now.
I did some more testing, and wanted to add to this thread for anyone else having the same issue.
The culprit is actually the Gigabyte App Centre application, which when installed, also installs something called EasyTune Engine Service. This service is required to run the Gigabyte applications for controlling motherboard settings like RGB lights and fan speed control, but it causes the CPU to operate at the base speed after a reboot. I tried different settings, but it always defaults to no Turbo boost after a reboot.
Uninstalling the EasyTune Engine Service renders the other apps (e.g. SIV for fan control) non operational, so I had to remove the App centre all together in the end, and control the fan settings from BIOS. After uninstalling all the Gigabyte utilities, the CPU is working properly again.