Temporary Solutions / Tips re. Bios 1604 issues
During runs at 5.3 GHz and other overclocking trickery, I ran into what many other folks have also experienced with certain Asus UEFI Bios (my current board is a Asus ROG Max V Extr., with bios 1604, and apparently other boards are affected as well. The original 'problem' occurred' after pushing my system past 5.3 GHz and trying out a few different settings, not all of them working well, so some freezes and a lot of rebooting > that seems to be the problems and also incorporates another solution, per below
...there were other posts elsewhere which talked about uninstalling 'Fanexpert2' - that helped alleviate the 'frozen multiplier state', even though I have been running Fanexpert2 again now for over a month in Bios 1604 without any issues, just following a simple rule re. rebooting below.
...when the original problem occurred, I noticed that Intel's excellent 'Extreme Tuning Utility' (XTU) also lost its ability to affect multiplier...running a software company for the past decade and a half, that told me that this is likely at least in part related to Windows & registry changes, perhaps affected by some settings in Asus AI Suite after a given number of crashes.
...so uninstalling AI Suite (all of it, including FanExpert) was step 1. I then uninstalled XTU, and reinstalled it, given me back the ability to affect multipliers in Windows via XTU...Then reinstalled just two parts of the AISuite (Turbo V, Digi+)...also worked fine.
...after upgrading the cooling system to a custom loop and getting ready for multiple HWBot record runs, I needed FanExpert2 and reinstalled it...that started to reintroduce the multiplier problem 'to some degree', setting it in the Bios (ie 50x) would still revert back to whatever AI Suite / TurboV had prior to rebooting. That confirmed that there is some interplay between Win7 registry, AI Suite and even XTU, which makes sense, given that they are Windows programs...NOW FOR THE 'TIP'...
...as indicated, preparing for record runs for my HWBot team necessitated leaving the 'daily comfort zone' settings and kicking it up a notch...and reintroduced the danger of FanExpert and other AISuite components going into some sort of 'safe mode' after rebooting from a freeze etc.
...a simple way to avoid it I have now tested on my MVE over 50 times is this: If you freeze because of too wild settings and having AiSuite (incl. FanExpert) installed even if not loaded, just let it boot back AT LEAST ONCE to a normal daily setting once WITHOUT making any changes, ie in multiplier, BCLK or vCore...may be open a simple program or two like email or a web browser, wait a few minutes and then boot down again.
I wish I could explain it better and I am not entirely sure myself yet as for the real reasons, but it seems letting Windows see a full cycle of 'no problems', freezes etc avoids some sort of lock which seems to affect the registry if it sees multiple boot cycles that all end in a freeze or crash.
After a 'healthy' boot-up and boot-down, then you can try some more crazy settings again...and a failure with those resulting in freezes will not lock you out from changing multipliers again as long as in the next boot cycle, you let it 'recover' per above...this has worked for me for many weeks now, complete w/FanExpert2 etc running and trying out all kinds of different HWBot run configurations.