BCLK and ICCAdvancedSetupDataVar

Dell G7 7500 Laptop, 10750h Bios v1.5.0

Recently figured out how to undervolt this laptop using UEFItool, IFRextractor and RU.efi, and was curious to see what else could be tweaked in it. I found the CPU multipliers and predictably, changing them has no effect. I ‘found’ the offsets for bits that seemingly control BCLK while browsing the bios in UEFItool, but the variable that they’re located in, ICCAdvancedSetupDataVar, doesn’t show up when I looked for it in RU.efi. I noticed in the extracted IFR for that section that it’s setup or defined just as ‘VarStore’, as opposed to VarStoreEFI:

VarStore: VarStoreId: 0xB [64192DCA-D034-49D2-A6DE-65A829EB4C74], Size: 0x8, Name: IccAdvancedSetupDataVar ← can’t find in RU.efi

VarStoreEFI: VarStoreId: 0x3 [B08F97FF-E6E8-4193-A997-5E9E9B0ADB32], Attrubutes: 7, Size: 334, Name: CpuSetup ← can find in RU.EFI

I also noticed that it doesn’t have any attributes, which I think indicate that it’s not NV, no boot-service access, and no runtime access.

My question is, is there a way to access this variable in RU.efi, another tool, or even after booting to OS? I’ve read that the BCLK is controlled by the ME; is this true for all intel CPUs/chipsets?

Thanks for any help. Because I’ve seen it asked alot in this forum, I have run MEinfo, and Measured and Verified Boot are enabled in FW and fuses.

Lastly, I do understand that tweaking the BCLK can only give very limited gains due to the effects on other components. I just find it very interesting to poke around and see what is possible.

You need only undervolt cpu?