Attempting to overclock a Precision M6800 & Failing (Collection of all my "research" and attempts)

[BYTEHAT248]

After countless hours of attempting to unlock the advanced menus in the precision M6800s, ive had no luck, even with posting asking about it on bios-mods.com, but I have learned quite a few things about modding the bios that may help others in doing what I was not able to or maybe someone could help me do it. so i compiled everything i found online (+ stuff i did on my own) about this to post it all here.

(My Precisions specs, ME Disabled, BIOS Ver A16, CPU: i7 4930MX, GPU: FirePro M6100, 12GB RAM, Fedora)

 

Before any thing else I should note that if your are going to attempt any of the things here, know that there is a chance you could brick your motherboard and the only way to fix it would be a external programmer.

 

Part 1: Modifying setup variables with setup_var in a grub prompt (if somebody wants what commands i ran to change the MSR values on linux let me know)
So when i got this machine i picked it specifically as a project computer, to try to push it to its absolute limits in terms of performance. So first i started researching gpu upgrades, i ended up finding that the GTX 1070 MXM is the best choice for me but it only works on linux. And then i started looking for ways online to overclock the CPU, and found, mostly nothing. Other than a post on a no longer existing forum.( https://www.nbrchive.net/forum.notebookreview.com/threads/guide-dell-precision-m6800-m4800-sbios-mod.788481/index.html ). The user (valuxin) that made that guide is also the person that made the Mystery Magic VBIOS for the FirePro M6100 (i currently have it on my card). So i thought why not try it. Well I changed all the variables to unlocked, and well i was able to change MSR values with the wrmsr command on linux, and while it did change the values, my cpu (i changed the values to turn off all power limits on the CPU and raise its max Turbo freq to 4.2ghz all cores), the only thing that it actually did was allow it to boost to 3.9ghz and hold it. according to turbostat it was not boosting past 3900mhz at all. So it was time to try something else

 

 

Part 2: Manually changing hex values with RU.efi
So i realized pretty fast it wasnt going to be as easy as i thought it was to overclock this thing, so i did some research and figured out that i could just manually write hex values with RU.efi, so i dumped my bios and opened it up in UEFITool and then extracted the setup PE32 Image, then i extracted the IFR tables. And then spent a while figuring out what was what until i figured out what needed to be changed 

 

The offsets needed to be changed were in var store 0x15 (Setup) they were: 0x23 (to 0A), 0x24 (to 2A), 0x25 (to 2A), 0x26 (to 29), 0x27 (to 29), 0x2F (to FF), 0x30 (to FF), 0x31 (to FF), 0x4C (to FF) .

I then saved and rebooted and Turbostat (and corefreq) was now saying that my CPU was set to boost up to 4.2ghz on 2 cores and 4.1ghz on 4 cores. But it still wasnt boosting past 3.9ghz.

(there was one other thing too, in RU there was a  var store called SystemAccess, in it was a single offset, 1 byte, it was set to 0x00, now i thought to myself, theres no way that wont do at least something, so i set it to 0x01, nothing. but when i went back to RU.efi it was set back to 0x00, i tried to set it to 0x01 again, i reboot and then go back into ru and its right back to 0x00, it was reseting itself, and since i didnt know what exactly it did, i just left it alone forgot about it)

So I thought that maybe i was going about it all wrong, maybe i just needed to figure out a way to unhide the advanced menu, or put one in.

 

 

Part 3: Attempting to unlock the advanced menu in the bios (and failing due to not knowing enough about bios modding)
So at this point i had kinda given up, i was only looking online and hoping to find some kind of guide or premade bios, and i did end up finding something (https://forums.mydigitallife.net/threads/tutorial-ami-aptio-uefi-advanced-menu-unlock-bonus-msr-unlock.54523/) a guide on how to unlock the advanced menus in the bios of the Precision M3800. Now the precision m6800 and m3800 are 2 very different computers, but they probably  both use the same base for there bioses since they are both M "800" series (yes i know they all use AMI bioses, but i mean a more configured base and considering i found references to DDR2 while looking super deep in my bios dump, a lot of dells computers probably do) so i decided why not try it on my pc, well i looked into the extraced setup IFR tables, and there was only one thing in the forum sets (and in the guide there was multiple things) Main (0x7). I even extracted the bios from the A26 bios setup, and it was the same thing. I had hit a brick and given up, but im hoping someone might be able to succeed where i had not.

 

 

In case they can be of use:

Full A16 BIOS Dump: https://drive.google.com/file/d/1lvxeWrr5YXE1Ik9rTQI8fZeElxgOpJUk/view?usp=sharing
Extracted IFR tables from setup: https://drive.google.com/file/d/1kocG4yWR4Gl5b8_eETgeSzZ8zU6Okqsj/view?usp=sharing
Full Extracted A26 BIOS: https://drive.google.com/file/d/13rtPeStXgEOflKnMWPqZy2vlLcFlKYPN/view?usp=sharing

[BYTEHAT248]

UPDATE: So my computer has been giving me very mixed signals, and i took that as the changing hex values to overclock did not work. but thinking about it more, it is able to boost to 3.9Ghz on all cores, something i did worked, and ive tried a few monitoring softwares, cpupower and turbostat both said that the CPU is set to boost to 4.2Ghz all cores, but it was maxing out on them at 3900Mhz (or 3.9Ghz). Now system monitor says that it is boosting to 4.2Ghz on some cores, but nothing in between 3.9Ghz and 4.2Ghz. So there is 2 things that could be happening. Number 1 is that the overclock did work, and it is boosting to 4.2Ghz but what i did to acheive that messed with sensors and it isnt showing the correct reading. Number 2 is that the CPU is still hitting a power draw limit and its not boosting because of that, even with turning off the power limits i found. And i think that number 2 is unlikely, cause after turning off the power limits and trying to game with a 240W charger, the screen got fuzzy as the CPU and GPU fought for power, and when i switched to a 330W charger it went away. I'd love to hear any suggestions of what to try next, because im starting to think i gave up on writing values to quickly, and there is potential.

[SuperMG]

Hello, what should we do to get the maximum of 4Ghz thru grub variables?

[BYTEHAT248]

Ive only tried this with bios ver A16 (these values could be different on different BIOS versions), but boot into RU.efi, select setup, change the value of 0x24 from 00 to 28, 0x25 from 00 to 28, 0x26 from 00 to 28, and 0x27 from 00 to 28, that would set it to 4Ghz All Core, you should also disable the overclocking locks and stuff too, guide for that here ( https://www.nbrchive.net/forum.notebookreview.com/threads/guide-dell-precision-m6800-m4800-sbios-mod.788481/index.html ). I should note that i was not able to get my i7-4930MX to actually boost past 3.9Ghz, but this guy might have solved that problem ( https://forum.level1techs.com/t/solved-cpu-scaling-governors-dont-work-my-computer-wont-obey-my-command/202241/18 ), I havent tried it yet. I am currently working on a actual BIOS mod to unlock hidden menus, but so far dell has made that impossible due to the way the bios is configured. 

Edited February 25 by BYTEHAT248

[SuperMG]

Hello, did you manage to unlock the Power Limits?

 

Did you get more than 58W? Like 65W?

[BYTEHAT248]

No, but im going to be looking into board modifications soon to do so. Im also going to try more heavy NVRAM editing sometime next week most likely, but I flashed a backup BIOS with a dirty ME without knowing, so I have to take it all apart to flash externally (since they dirty ME prevents flashing normally). This forum post kinda shows where I am currently with the mod, as ive taken a bit of a break to work on VBIOS modding. https://winraid.level1techs.com/t/need-help-precision-m6800-bios-modding/114641

[SuperMG]

1 hour ago, BYTEHAT248 said:

No, but im going to be looking into board modifications soon to do so. Im also going to try more heavy NVRAM editing sometime next week most likely, but I flashed a backup BIOS with a dirty ME without knowing, so I have to take it all apart to flash externally (since they dirty ME prevents flashing normally). This forum post kinda shows where I am currently with the mod, as ive taken a bit of a break to work on VBIOS modding. https://winraid.level1techs.com/t/need-help-precision-m6800-bios-modding/114641

The only issue is the power limits. I can't seem to unlock them. Despite editing the values, they don't change anything.

 

But on the Dell Precision M4800, I see people with 4910MQ and 4940MX being able to overclock past 4.2GHz 

[Bublik]

Hi SuperMG,
Based on my experience with the M4800 and, similarly, the M6800, there is a BIOS bug where the TDP and power settings can be edited in NVRAM but are not applied. You can “work around” this by putting the laptop into sleep mode after startup and then waking it up again. Then overclocking works on all cores, and the TDP values are applied correctly. The only important thing is that the battery is fully charged; if not, it won’t work. This must be done again with every reboot.

 

Edited Saturday at 10:14 AM by Bublik
Screenshot attached

[SuperMG]

On 4/4/2026 at 2:51 AM, Bublik said:

Hi SuperMG,
Based on my experience with the M4800 and, similarly, the M6800, there is a BIOS bug where the TDP and power settings can be edited in NVRAM but are not applied. You can “work around” this by putting the laptop into sleep mode after startup and then waking it up again. Then overclocking works on all cores, and the TDP values are applied correctly. The only important thing is that the battery is fully charged; if not, it won’t work. This must be done again with every reboot.

 

Sadly, I don't think, it doesn't work on my 4900MQ. I have some good battery, 100%, 240W PSU. Unlocked every power limit crap in the NVRAM. Doesn't work.

 

I have 3.8GHz all cores, 58.9W max

 

Put it in sleep mode then waking it up shortly, test stuck at 58W very bad. Then going to sleep mode then waking it up, same issue.

 

Your 4900MQ. What about CPU-Z score?

Edited yesterday at 03:42 PM by SuperMG

[Bublik]

That's strange; I can say with certainty that it works. I've already tested it on three laptops (M6800 LVDS, 2x M4800 (LVDS & eDP)) with different processors. I think there must be a small detail missing somewhere.

Perhaps describing my approach in more detail will help you find the error.

 

Just to be safe, I accept no liability for any damage that may result from following these instructions. Everyone must use their own judgment and, if necessary, accept the consequences. 

 

1. Changed the following variables according to Valuxin's instructions (STEP 1):

 

--CFG lock, Variable: 0xC8A
--VR Current value lock, Variable: 0xC93
--Package power limit lock, Variable: 0xC94
--Overclocking lock, variable: 0xC95
--Platform power limit lock, variable: 0x54
--Config TDP LOCK, variable: 0x3A
--ICC Locks After EOP, variable: 0xC14

 

Link to the instructions:

 

2. If the NVRAM variable was successfully modified, you should no longer see any padlocks in the “Turbo Power Limits” window in ThrottleStop, just as with the “TDP Level” option. If padlocks are still visible, you’ll need to repeat step 1. This happened to me once.

 

 

In this window, set the desired values for PL1, PL2, and PP0, then click the “Apply” button.

 

3. In the Turbo FIVR Control window, under Turbo Ratio Limits, enter the desired values. Check the “Overclock” box and click the “Apply” button.

 

 

4. Now put the laptop into sleep mode (I do this using the keyboard keys, but I don’t think it matters) and wake it up.

 

In the Limits window, only the applicable limits should be displayed under load, such as PL1 or PROHOT. “EDP CURRENT” only appears occasionally for me, mostly when the CPU is idle. If no limits are displayed in this window, my CPU maintains a constant 4GHz in the ThrottleStop benchmark. Most of the time, however, my M4800 experiences temperature issues and then throttles down.

 

A quick note: Step 1 only needs to be performed once. These settings remain in effect as long as the CMOS battery is not removed. Removing the CMOS battery will reset the NVRAM variables to their default values. 

 

As for Linux, I’m afraid I can’t say how it works there.

 

Regarding your question about CPU-Z: Thanks to Windows 11 (with its over 250 background processes), I get around 410/2010 points (single-thread/multi-thread), sometimes even less.

 

 

 

 

 

 

[BYTEHAT248]

54 minutes ago, Bublik said:

That's strange; I can say with certainty that it works. I've already tested it on three laptops (M6800 LVDS, 2x M4800 (LVDS & eDP)) with different processors. I think there must be a small detail missing somewhere.

Perhaps describing my approach in more detail will help you find the error.

 

Just to be safe, I accept no liability for any damage that may result from following these instructions. Everyone must use their own judgment and, if necessary, accept the consequences. 

 

1. Changed the following variables according to Valuxin's instructions (STEP 1):

 

--CFG lock, Variable: 0xC8A
--VR Current value lock, Variable: 0xC93
--Package power limit lock, Variable: 0xC94
--Overclocking lock, variable: 0xC95
--Platform power limit lock, variable: 0x54
--Config TDP LOCK, variable: 0x3A
--ICC Locks After EOP, variable: 0xC14

Just so you are aware, from what ive seen those variables, well vary between certain bios versions (ex. A25, A26, A05) and changing the wrong ones can cause your laptop to not boot. To fix that you would need to clear CMOS. Those variables are from A16, the version I choose to try and mod, so if you need some other variables, I can go and find em for you. Also I think I might try and figure out a way to do the power limit unlock thing on linux as they're are ways to change msr values on the fly.

[SuperMG]

15 hours ago, Bublik said:

That's strange; I can say with certainty that it works. I've already tested it on three laptops (M6800 LVDS, 2x M4800 (LVDS & eDP)) with different processors. I think there must be a small detail missing somewhere.

Perhaps describing my approach in more detail will help you find the error.

 

Just to be safe, I accept no liability for any damage that may result from following these instructions. Everyone must use their own judgment and, if necessary, accept the consequences. 

 

1. Changed the following variables according to Valuxin's instructions (STEP 1):

 

--CFG lock, Variable: 0xC8A
--VR Current value lock, Variable: 0xC93
--Package power limit lock, Variable: 0xC94
--Overclocking lock, variable: 0xC95
--Platform power limit lock, variable: 0x54
--Config TDP LOCK, variable: 0x3A
--ICC Locks After EOP, variable: 0xC14

 

Link to the instructions:

 

2. If the NVRAM variable was successfully modified, you should no longer see any padlocks in the “Turbo Power Limits” window in ThrottleStop, just as with the “TDP Level” option. If padlocks are still visible, you’ll need to repeat step 1. This happened to me once.

 

 

In this window, set the desired values for PL1, PL2, and PP0, then click the “Apply” button.

 

3. In the Turbo FIVR Control window, under Turbo Ratio Limits, enter the desired values. Check the “Overclock” box and click the “Apply” button.

 

 

4. Now put the laptop into sleep mode (I do this using the keyboard keys, but I don’t think it matters) and wake it up.

 

In the Limits window, only the applicable limits should be displayed under load, such as PL1 or PROHOT. “EDP CURRENT” only appears occasionally for me, mostly when the CPU is idle. If no limits are displayed in this window, my CPU maintains a constant 4GHz in the ThrottleStop benchmark. Most of the time, however, my M4800 experiences temperature issues and then throttles down.

 

A quick note: Step 1 only needs to be performed once. These settings remain in effect as long as the CMOS battery is not removed. Removing the CMOS battery will reset the NVRAM variables to their default values. 

 

As for Linux, I’m afraid I can’t say how it works there.

 

Regarding your question about CPU-Z: Thanks to Windows 11 (with its over 250 background processes), I get around 410/2010 points (single-thread/multi-thread), sometimes even less.

 

 

 

 

 

 

Wow. I just needed to check "OVERCLOCK" checkbox. Now it boosts at 3.9GHz!

 

Yes everything else you said, I did them. They are right to unlock every locked crap.

 

I can reach 65W finally. Edit: Nevermind, back to 58.9W after enabling Overclock checkbox but with higher frequencies when different loads. I tried tomorrow but now I can't get the power limit to hit 65W... My battery is at 98% somehow and it doesn't charge. I replaced the battery and the AC adapter (240W) again but it doesn't work

 

396 single-thread and 2073 in multi-thread. I have a higher single-thread than my Xeon E5-1680 v2 at 3.8GHz full.

 

Yeah the 4900MQ is better than the 4940MX, no need for the extra current and extra TDP.

 

ICC Locks After EOP, variable: 0xC14 at 0x05 for all unlocked

Edited 6 hours ago by SuperMG