The I7 9700K may not be turbo boosting.
The I7 9700K may not be turbo boosting.
I encountered a problem with my Asus Prime Z370A-II paired with an i7-9700K processor. After installing the BIOS update to version 0801, the system booted successfully at 4.6GHz and adjusted as needed. Previously, it stuck at 3.8GHz unless I manually overclocked it in the BIOS. The XMP I profile for RAM and virtualization worked without affecting the CPU clock.
The latest prime95 release is version 29.8, build 3. Source: mersenne.org
You can easily fix the issue using your ASUS UEFI/BIOS. Each CPU comes with its own firmware update from ASUS. Visit the ASUS Download Center, search for your motherboard, and go to "CPU / Memory Support." There should be your specific CPU's BIOS file listed. Download it, create a bootable USB from the zip folder, and flash it as you would a regular BIOS update. If the system confirms you already have the latest version, proceed with the update. Hope this resolves your problem!