I have a 12900K with an Asus Z690 Extreme motherboard (bios 811) and a Ryujin II AIO and recently decided to enable AI Overclocking in the BIOS.
Up until then the stock CPU core speed in Windows 11 at idle was 4900 Mhz, as reported by CPU-Z. With AI Overclocking enabled, the idle core frequency jumped to 5300 Mhz, so a 400 MHz overclock (voltage and therefore idle and load temperatures also increased by a lot, of course).
I'm not sure if it happened during the first or second reboot after enabling AI Overclock, but I got startled by a message from the BIOS stating that it had collected enough samples for my cooler and if I wanted to turn cooler performance prediction off (something like that, don't remember the exact words). I said No because ambient temperatures have been fluctuating a bit here and I wanted the algorithm to keep learning with the overclock. Perhaps this was a mistake.
What I have noticed since then is that the actual overclock fluctuates A LOT every time I wake my PC up from sleep. Sometimes it will idle at 5300 Mhz, otherwise at 5200 Mhz, but I have seen it go as low as 5000 Mhz. This idle frequency will remain constant until I either reboot the PC or wake it up from sleep again (PC is always on).
When idle frequency is 5300 MHz, Vcore will usually be around 1.47v, at 5200 MHz, Vcore is around 1.4v. Personally I think an overclock to 5200 MHz is the best balance between temperatures and higher frequencies.
The day I saw the AI overclock go all the way down to 5,000 MHz and remain there, I ran Cinebench for a handful of minutes and the next time the PC woke up from sleep the overclock was back up to 5,300 MHz.
So, my questions are:
1. Why so much fluctuation in terms of the automatic AI overclock? Is it because I told it to keep sampling the cooler? Should I tell it to stop sampling it in the BIOS or is it actually better/safer to let the system decide what is the best overclock at any given time based on whatever the algorithm tells it to (ambient temperature might have something to do with it, perhaps) ?
2. Is there any way to "lock" the AI overclock to 5200Mhz or is that accomplished simply by telling it to stop sampling the performance of the AIO cooler?
3. As I said, at 5,300 Mhz vCore goes all the way up to 1.47v. Is there an option in the BIOS to provide a slight negative offset to this voltage to keep temperatures at load a bit more under control (of course, I would then have to test to make sure the system still remains stable at the lower voltage).