Can the i5-8250u's long term power limit be raised above 25W using a modded bios?

[Hentrox]

Hey there, I've searched the internet and am unable to find out the answer to my question. I am wondering if you are able to lend any assistance..

 

Is the possible that the i5-8250u's long term power limit can be raised above it's Intel "configurable TDP-up" (25W) with a modded bios, or is this 'locked' by Intel?

 

(My laptop is the Acer Aspire A515-51G-55F1)

 

NOTE: I am using a semi-custom cooling solution so cpu will be fine. Someone I know has told me that the vrm components will be okay with 45W with a fan directly pointed at them. And I am using an egpu (via ADT-LINK R43SG) so the 65W power adapter will not overload.

Edited September 20, 2021 by Hentrox

[adarw]

why do you want to do this? 

[Levent]

I am not sure how it is set. It is most likely set in bios, you also should check to see if you laptop ever came with a higher TDP CPU. If it didnt, you might be VRM limited too.

[TukangUsapEmenq]

I don't think increasing the power to the CPU higher than usual is a good idea. It could end with your motherboard died, VRM toasted, and *poof* the power brick.

 

Take the advice from someone recently lost his laptop because of an experiment: don't, just don't.

[unclewebb]

8 hours ago, Hentrox said:

i5-8250u

The 8th Gen U CPUs are very flexible and you can run them well beyond their 15W TDP rating.

 

 

8 hours ago, Hentrox said:

'locked' by Intel

Intel does not lock the power limits of these CPUs. It is usually Acer that uses an embedded controller (EC) to enforce the 15W TDP rating. 

 

I doubt your Acer laptop will let you run at the configurable TDP-up 25W level for any length of time. Acer usually clamps these CPUs down to 15W. I do not know of anyone that has been able to work around this Acer limitation. 

 

The Lenovo C930 in the above screenshot has unlocked power limits and does not use the EC so it was easy to go beyond 15W. 

 

Run ThrottleStop and post a screenshot of the TPL window. There are 3 unique sets of power limits that control Intel CPUs. ThrottleStop gives you access to the MSR and MMIO power limits but there are still the EC power limits that some companies use. If the MSR and MMIO power limits are both set appropriately and your computer still power limit throttles, it is the EC power limits that are in control. There is no easy way to reprogram or modify the EC limits. 

[Hentrox]

12 hours ago, adarw said:

why do you want to do this? 

To play valorant with more fps

[Hentrox]

8 hours ago, unclewebb said:

The 8th Gen U CPUs are very flexible and you can run them well beyond their 15W TDP rating.

 

 

Intel does not lock the power limits of these CPUs. It is usually Acer that uses an embedded controller (EC) to enforce the 15W TDP rating. 

 

I doubt your Acer laptop will let you run at the configurable TDP-up 25W level for any length of time. Acer usually clamps these CPUs down to 15W. I do not know of anyone that has been able to work around this Acer limitation. 

 

The Lenovo C930 in the above screenshot has unlocked power limits and does not use the EC so it was easy to go beyond 15W. 

 

Run ThrottleStop and post a screenshot of the TPL window. There are 3 unique sets of power limits that control Intel CPUs. ThrottleStop gives you access to the MSR and MMIO power limits but there are still the EC power limits that some companies use. If the MSR and MMIO power limits are both set appropriately and your computer still power limit throttles, it is the EC power limits that are in control. There is no easy way to reprogram or modify the EC limits. 

I have uploaded the screenshot. I did mess around with throttlestop and xtu in the past and nothing seemed to change PL1.

 

So, are you saying, even if I unlock the engineering/advanced settings in the bios by physically flashing a modded bios, I still cannot change PL1 due to there being a separate physical EC which controls/locks it?

[unclewebb]

5 hours ago, Hentrox said:

EC

Set the ThrottleStop TPL window up so it looks like this.

 

 

Setting PL1 and PL2 to 44W will take care of the MSR power limits. Checking the MMIO Lock option will take care of the MMIO power limits. Press OK and run a benchmark like Cinebench R20 while the Limit Reasons window is open.

 

https://www.techpowerup.com/download/maxon-cinebench/

 

Are you seeing any PL1 or PL2 power limit throttling in Limit Reasons while the CPU is fully loaded running this test? Is this throttling happening at 15W or less? If power limit throttling is happening at way less than the 44W limit that you just set then it must be the EC that is limiting your CPU.

 

You can try flashing a modified BIOS as long as you are sure that it is safe to do so. No point in bricking your laptop trying to solve this limitation. I do not think a modified BIOS is going to solve this problem. With a modified BIOS you might be able to change the MSR and MMIO power limits. I do not think a modified BIOS is going to change the EC power limit. 

 

If you do install a modded BIOS, delete the ThrottleStop.INI configuration file before running ThrottleStop. This will delete your previous power limit settings that are stored in this file. 

 

[Hentrox]

50 minutes ago, unclewebb said:

Set the ThrottleStop TPL window up so it looks like this.

 

 

Setting PL1 and PL2 to 44W will take care of the MSR power limits. Checking the MMIO Lock option will take care of the MMIO power limits. Press OK and run a benchmark like Cinebench R20 while the Limit Reasons window is open.

 

https://www.techpowerup.com/download/maxon-cinebench/

 

Are you seeing any PL1 or PL2 power limit throttling in Limit Reasons while the CPU is fully loaded running this test? Is this throttling happening at 15W or less? If power limit throttling is happening at way less than the 44W limit that you just set then it must be the EC that is limiting your CPU.

 

You can try flashing a modified BIOS as long as you are sure that it is safe to do so. No point in bricking your laptop trying to solve this limitation. I do not think a modified BIOS is going to solve this problem. With a modified BIOS you might be able to change the MSR and MMIO power limits. I do not think a modified BIOS is going to change the EC power limit. 

 

If you do install a modded BIOS, delete the ThrottleStop.INI configuration file before running ThrottleStop. This will delete your previous power limit settings that are stored in this file. 

 

I set the settings as shown in my screenshot and applied them then ran cinebench and cpu package started at 30W then power throttled down to 15W after 5-10 seconds and stayed there. It's ok if I brick my bios I can just flash the original one back on or an unbricked unlocked one (I'm going to use a SPI programmer flashing tool which clips to the bios chip and force flashes it using another pc). If I do somehow end up causing permanent damage to the laptop (although I don't how I could if I'm sensible about it - don't fry vrm's or anything), its ok because it only cost me $150NZD.

 

The SPI Programmer should arrive in the next week, so I'll post an update here after I've flashed an unlocked bios.

 

Thanks for your insight so far.

 

Side note: guy in the comments section of this post seems to think there isn't an 'embedded controller'   https://www.reddit.com/r/intel/comments/prp2gv/can_the_i58250us_long_term_power_limit_be_raised/

 

[Hentrox]

23 hours ago, adarw said:

why do you want to do this? 

More FPS in Valorant  (I have an egpu)

[unclewebb]

9 hours ago, Hentrox said:

seems to think there isn't an 'embedded controller'

Quote

They can be changed at any time by the OS and there is nothing an external controller can do to stop you from changing them.

He is partially correct. The MSR and MMIO power limits can be changed or locked by software or the OS at any time. You have set the MSR and MMIO power limits appropriately and your CPU is still throttling to 15W. There must be another power limit holding you back. The third set of turbo power limits are managed by the EC.

 

9 hours ago, Hentrox said:

SPI Programmer

As long as you have one of those you should be OK. Some people jump into these things without being fully prepared. 

 

9 hours ago, Hentrox said:

I'll post an update

That would be great. I am as curious as you are to find a way to get beyond the 15W TDP limit.

 

Some MSI laptops let you access the IMON Slope variable in their advanced BIOS. You can adjust this so the CPU incorrectly reports power consumption. If you set the Slope to 50 instead of 100, when your CPU is consuming 30W, the CPU will only report that it is consuming 15W. After you do this, the CPU has no more reason to power limit throttle until it hits 30W instead of the 15W limit. Power consumption reported by Intel CPUs is not measured power consumption. It is a calculated approximation that can be manipulated by adjusting IMON Slope and IMON Offset.

 

If you have access to an advanced BIOS, you might be able to access these settings. That is the only way that I know to get beyond the 15W EC enforced power limit.  

[Hentrox]

4 hours ago, unclewebb said:

He is partially correct. The MSR and MMIO power limits can be changed or locked by software or the OS at any time. You have set the MSR and MMIO power limits appropriately and your CPU is still throttling to 15W. There must be another power limit holding you back. The third set of turbo power limits are managed by the EC.

 

As long as you have one of those you should be OK. Some people jump into these things without being fully prepared. 

 

That would be great. I am as curious as you are to find a way to get beyond the 15W TDP limit.

 

Some MSI laptops let you access the IMON Slope variable in their advanced BIOS. You can adjust this so the CPU incorrectly reports power consumption. If you set the Slope to 50 instead of 100, when your CPU is consuming 30W, the CPU will only report that it is consuming 15W. After you do this, the CPU has no more reason to power limit throttle until it hits 30W instead of the 15W limit. Power consumption reported by Intel CPUs is not measured power consumption. It is a calculated approximation that can be manipulated by adjusting IMON Slope and IMON Offset.

 

If you have access to an advanced BIOS, you might be able to access these settings. That is the only way that I know to get beyond the 15W EC enforced power limit.  

Can I just clarify what you are saying. Are you saying that due to the embedded controller it is literally impossible to change the long term power limit (in a sense that is shows the correct power consumption on software, so not by changing IMON slope and offset)?

[unclewebb]

18 minutes ago, Hentrox said:

embedded controller

I believe that during any long term test, the EC will always send the 15W TDP limit to the CPU. I do not think that you can mod the BIOS to change this. 

 

The only known work around for this issue is to change the IMON Slope value. This can be used to literally trick the CPU. The CPU will think that power consumption is far less than what it actually is.

 

Depending on what you set the IMON Slope value to, you can trick the CPU so when it is actually consuming 30W or 40W, you can have the CPU thinking that it is still under 15W. When done correctly, all monitoring software will report a low power consumption number. The CPU compares this low reported power consumption number to the 15W number that the EC is sending it and will decide that it does not have any need to power limit throttle. This allows the CPU to continue running at its full rated speed. No more power limit throttling. 

 

After you do this, the only throttling will be thermal throttling if the CPU gets too hot. I will try to find a picture that shows how much fun you can have.

[Hentrox]

1 minute ago, unclewebb said:

I believe that during any long term test, the EC will always send the 15W TDP limit to the CPU. I do not think that you can mod the BIOS to change this. 

 

The only known work around for this issue is to change the IMON Slope value. This can be used to literally trick the CPU. The CPU will think that power consumption is far less than what it actually is.

 

Depending on what you set the IMON Slope value to, you can trick the CPU so when it is actually consuming 30W or 40W, you can have the CPU thinking that it is still under 15W. When done correctly, all monitoring software will report a low power consumption number. The CPU compares this low reported power consumption number to the 15W number that the EC is sending it and will decide that it does not have any need to power limit throttle. This allows the CPU to continue running at its full rated speed. No more power limit throttling. 

 

After you do this, the only throttling will be thermal throttling if the CPU gets too hot. I will try to find a picture that shows how much fun you can have.

Interesting! It would be nice to knowledge how much power is being consumed because then I could know how much power I'm putting through vrms etc. Is there a way to calculate it based on the IMON ratio/curve?

 

 

[unclewebb]

5 minutes ago, Hentrox said:

IMON ratio

I think this is fairly simple. If you set the slope to 50% then reported power consumption will be half of actual power consumption. Monitoring software that shows 15W should be equivalent to 30W actual. 

 

Here is a similar trick. My laptop 4700MQ is fully loaded with 8 threads of a benchmark test. Check out the reported power consumption. Actual power consumption is probably somewhere around 60W. 

 

Do some Google searching for IMON Slope and IMON Offset to learn more. 

 

[Hentrox]

6 minutes ago, unclewebb said:

I think this is fairly simple. If you set the slope to 50% then reported power consumption will be half of actual power consumption. Monitoring software that shows 15W should be equivalent to 30W actual. 

 

Here is a similar trick. My laptop 4700MQ is fully loaded with 8 threads of a benchmark test. Check out the reported power consumption. Actual power consumption is probably somewhere around 60W. 

 

Do some Google searching for IMON Slope and IMON Offset to learn more. 

 

Interesting! Now I just have to wait for the SPI Programmer to arrive then I can start tinkering 

 

[unclewebb]

2 minutes ago, Hentrox said:

Interesting!

It looks like actual power consumption during a TS Bench 8 Thread test is 52W not 60W.

Same temperatures and same CPU load but big difference in reported power consumption compared to the previous picture at 3.4W.

 

[Hentrox]

3 minutes ago, unclewebb said:

It looks like actual power consumption during a TS Bench 8 Thread test is 52W not 60W.

Same temperatures and same CPU load but big difference in reported power consumption compared to the previous picture at 3.4W.

 

Wait I thought you said that when you change IMON settings it doesn't show in software sensors, yet your throttlestop is showing 52.4W..? 

[unclewebb]

@Hentrox It shows 52.4W at default settings when not using any tricks. That was my before and after test.

 

It only shows 3.4W when the CPU is incorrectly reporting power consumption for the exact same load. 

 

 

[Hentrox]

16 minutes ago, unclewebb said:

@Hentrox It shows 52.4W at default settings when not using any tricks. That was my before and after test.

 

It only shows 3.4W when the CPU is incorrectly reporting power consumption for the exact same load. 

 

 

Oh right, I assumed that your default long term power limit would be a lot lower than 52W - must be a really beefy laptop!

 

 

[unclewebb]

The 4700MQ has a default long term TDP limit of 47W. The short term limit is 20% higher so PL2 is set to 56W. At default settings, for a short period of time, it will initially run at full speed during this benchmark but long term, it would always throttle down so it does not exceed the 47W limit. 

 

With the power limit trick, it is able to run at its full rated speed with a constant 34.00 multiplier indefinitely. The CPU checks and sees that power consumption is only 3.4W so there is no reason for the CPU to power limit throttle.

[Hentrox]

7 minutes ago, unclewebb said:

The 4700MQ has a default long term TDP limit of 47W. The short term limit is 20% higher so PL2 is set to 56W. At default settings, for a short period of time, it will initially run at full speed during this benchmark but long term, it would always throttle down so it does not exceed the 47W limit. 

 

With the power limit trick, it is able to run at its full rated speed with a constant 34.00 multiplier indefinitely. The CPU checks and sees that power consumption is only 3.4W so there is no reason for the CPU to power limit throttle.

LOL. So the cpu thinks its running at 3.4W? that's crazy. You must have really changed that IMON ratio/slider by a LOT to make 47W appear as 3.4W...

[unclewebb]

The 4th Gen mobile CPUs used a different trick but it accomplishes the same thing. Reported power consumption is not measured within Intel CPUs. It is only a calculated estimate. With the right tricks, the reported power consumption data can be manipulated.

[Hentrox]

2 hours ago, unclewebb said:

The 4th Gen mobile CPUs used a different trick but it accomplishes the same thing. Reported power consumption is not measured within Intel CPUs. It is only a calculated estimate. With the right tricks, the reported power consumption data can be manipulated.

Ah I see. 

[Hentrox]

@unclewebb I have unlocked advanced bios. HOLY HEKA THERE IS A LOT OF OPTIONS!! This is going to be a bloody mission to understand LOL