CPU speed at 0.48Ghz during low battery

It is possible that the hardware is overriding user settings in a low battery situation. If that is the case there is nothing you can do.

I think that I am getting somewhere!

First, I will address each of the solutions.

Bree said:

Perhaps a silly question, but there's a 'Maximum processor state' setting there too. What's that set to?

The maximum processor state is also set to 100%!

Berton said:

A month old? Should be in warranty, battery also, 1-year unless extended was purchased. But most replacement batteries carry only a 1-year warranty.

I do not believe that the battery or hardware is at fault, so I will not be returning the laptop. :)

LMiller7 said:

It is possible that the hardware is overriding user settings in a low battery situation. If that is the case there is nothing you can do.

Yes, I believe that this is the case.

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Okay, now for what I hope is the solution!

My laptop is a Lenovo Yoga 500-15IBD. I found that this problem is very common among Lenovo laptops, and the only way to solve it is to download a program called ThrottleStop and turn off the 'BD PROCHOT' setting. This had an immediate effect: my laptop is now below 30% (this is the point that it previously throttled) and running at the full 1.98Ghz.

This is the information helped me (from this Lenovo forum)

I have spent a long time looking into this issue and it appears that the fault is not directly with Lenovo. However, there are steps you can take to remedy it.

BD PROCHOT (Bi Directional PROCessor HOT) is a warning on Intel processors that allows the rest of the machine (both hardware and software) to throttle the CPU. It is designed as a precaution against overheating in small form factor machines, like the Yoga 500 series as discussed in this forum post.

There are no built-in ways to remedy this, no version of BIOS currently available for this series allows the user to disable the warning, and no operating system I am aware of is able to turn it off by default. Therefore power settings do not affect it as the warning is lower-level than the operating system.

The setting for changing this warning is located at position 0x1FC on the CPU register, decrementing the value at this address by one (for example: address value is 262239, change it to 262238) turns off the warning.

On Windows operating systems this is not necessary as ThrottleStop (available at the link at the bottom of this post) is capable of disabling the warning.

Again, the problem is NOT anything to do with the operating system, and therefore screenshots of power settings are useless. No BIOS versions provided by Lenovo for these systems allow the user to turn off the warning.

As for recreating the throttling at ~30% (the threshold may be slightly lower) there are no special steps to be taken. Simply allow the laptop to use its battery until it is very low, and then observe the CPU throttling. An easy way to tell whether the system is throttling is to try to scroll on a webpage in Google Chrome. The framerate will not be smooth. You can also open Command Prompt on any Windows system and use the command "wmic cpu get CurrentClockSpeed" to confirm that the clock speed of the CPU is significantly lower than it would usually be. For example, the i5-5200U processor on my 15IBD system is supposed to be capable of 2.2 GHz, but when throttling it was limited to 500 MHz, less than a quarter of what it should be running at.

BD PROCHOT is a system warning intended for maintaining safe operating temperatures, but it appears to be enabled when charging or on low battery for power saving purposes, as neither of those states should affect the temperature of the machine and I cannot imagine why else it would be activated.

I am not sure if the fault lies with Lenovo or Intel, but hopefully you will be able to liaise with Intel in order to remedy this issue.


I would have provided screenshots and BIOS versions but I used ThrottleStop to work around the issue six months ago, as shown by my last post in this thread. I do not currently have the laptop with me. In lieu of that I hope that the information I have provided has been useful, and please contact me if I can be of any further help. I have spent a long time trying to solve this issue and would like to be able to help others solve it more quickly.

Let's hope that this issue is now resolved.

Many thanks to everyone who posted, all the help is appreciated. :)