[Problem] Buggy Throttle on Dell Precision M6800

my i7 4800mq power throttles to well below what it can actually handle, even when on AC power. i am always on AC power, so this is a huge problem. I want my computer to obey my OS when it comes to cpu frequencies and things. Dell’s buggy bios is in the way.

i am on BIOS A25 and i have extracted the IFR tables. it will not allow me to post .txt files here, so here is a link to the Level1techs forum which documents my struggles with this so far. the linked post contains a download of my ifr tables.

i am now at the limit of my comprehension, i have looked through the ifr.txt but its not obvious to me how i can actually use the information to achieve my desired result.

Edit by Fernando: Thread title customized

"however many of the links are dead or the tools linked dont work (for bios A25). i also do not have access to Windows on this machine. using BIOS A16 is not an option for me. i am on A25, any other BIOS version make my system unbootable.

any AMI bios wizards able to help me out here?"

That article looks ok, but maybe the ME FW image on latest bios requires more recent tools that you can get here:
Intel (Converged Security) Management Engine: Drivers, Firmware and Tools (2-15) - Special Topics / Intel Management Engine - Win-Raid Forum

ME Analyzer: Intel Engine Firmware Analysis Tool Discussion - Special Topics / Intel Management Engine - Win-Raid Forum

[Guide] Unlock Intel Flash Descriptor Read/Write Access Permissions for SPI Servicing - Special Topics / Intel Management Engine - Win-Raid Forum

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my ME is disabled. laptop shipped like that, even confirmed by a little sticker underneath the battery. i suspect is why the fn+shift 15324 and fn+c trick doesnt work.

That should be initially referred…
No dump/flash with ME tools then only working with an SPI IC programmer, regular flash methods will be OEM/AMI blocked, using mod files.
Good luck.

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Sweet! So there IS a way to make my laptop do as i command… how do i do that?
Ive never manually burned a chip before. Nor created a bios mod file.
My soldering ability is non-existant.
Or is there a way to re-enable my ME and then re-disable it after ive fixed the behavior?

I do have access to windows, but a linux solution would be ideal. Is there any guides for doing these mods?

There’s no specific Linux guides, but there’s tools (but not all…) for other platforms including Linux, the actions are the same. the steps are the same, the warnings are the same…
PS: Without reading no learning, no learning leads to unnecessary questions.

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it would seem that any fix for this would require replacing the bios chips, which this laptop has 2 of. because i cannot find any way to burn a non-official bios while its still on the motherboard.

So I used the rapl interface through /sys/ to set the power limits threshold to an unreasonable high wattage, and the throttle times to 0. This did not help.

I am able to apply values to msr 0x150 during runtime, due to some kernel hacks I’ve come up with, on top of reverting the BIOS to A19. However, I have yet to find any values I can write to this in order to improve the system behavior.

I am now comfortable changing between official BIOS versions, since I’ve seen that the downgrade and upgrade process is reliable.

I am now suspecting that either my coin cell and/or main laptop battery might be failing and causing this issue. Even though I exclusively use the laptop while on AC power.

My ac adapter is not a problem. I have enable adapter warnings set and the BIOS has no issues with the Dell 330w charger. I also have Dell 240w and 90w chargers, all of which the BIOS claims to recognize as genuine and I observe no change in behavior between them, other than the system shuts off anytime I use the GPU when powered by the 90w one.

I have disabled turbo and successfully got the system to attempt to keep at only 2.7GHz. But it still has the throttle issue, this rules out boost being the problem. For now, I will keep boost disabled, and maybe try it again if I can first get it to maintain 2.7GHz.

I have a replacement coin cell ordered. I’ll order a replacement main battery when I can save up for it.

I also suspect microcode might have something to do with it. But I can’t find any documentation on what each microcode revision does.

I managed to get it to boot with bios a16. Which supposedly can be unlocked, but there is a signature check that I can’t find out how to disable.

ive done some testing. and the issue is definitely a false assertion of PROCHOT. even though this happens at only 67C!

https://gist.githubusercontent.com/mathew2214/306280afb4921b262d5de0ef577b82f9/raw

this is my ifr dump. altough im not seeing anything in there that would enable me to simply do setup_var do fix the throttle.