This message was posted on behalf of Intel Corporation
Thank you for joining our Intel ® Community.
In this case, please consider that Intel® does not recommend underclocking Intel® graphics frequencies. Under/Overrclocking might reduce system stability and useful life of the system, processor, and other system components; cause the processor and other system components to fail; cause reductions in system performance; and affect system data integrity. Intel® has not tested, and does not warranty, the operation of the processor beyond its specifications. Intel® assumes no responsibility that the processor and other system components, including if used with altered clock frequencies and/or voltages, will be fit for any particular purpose.
Also we do not support underclocking on the Intel® NUCs, and using them out of specs may void the warranty.
My recommendation is to follow the guidelines in the following document, in case that you want to change the default value settings of your device:
Even if we do not provide active support for this case scenario, we will keep your thread open in case that a community peer jumps in with a piece of advise.
I hope this helps.