Thinkpads Forum

Yesterday, after re installation of the operation system I noticed that no matter what, the frequency of my laptop's cpu(Core2Dup P8600) is restricted to 1.6Ghz(multiplier 6) even on full system load.
This only happens on AC power. When I disconnect the power adapter from the laptop, the frequency can go up to 2.4Ghz running only on battery(as it should when running on AC power)
I am using 65W adapter.
I will appreciate some help.
p.s My battery is almost dead(only 2% remaining capacity)
In windows event viewer I have events like this

Kernel Processor Power EventID 37, type WARNING

The speed of processor 1 in group 0 is being limited by system firmware. The processor has been in this reduced performance state for 71 seconds since the last report.

1) If you have such an option, try a 90W adapter and see what happens
2) If you have such an option, try a good battery and see what happens

dr_st wrote:1) If you have such an option, try a 90W adapter and see what happens
2) If you have such an option, try a good battery and see what happens

I have neither other battery, nor more powerful adapter. I have 2 adapters, but they all are 65W adapters.
I just want to know - is this normal behavior or there is something wrong?
I've updated my BIOS about year ago, because there was a problem with reading the data from the accelerometer sensor, needed for the Active Protection System to work. Should I try to perform BIOS downgrade?

Generally, when running without any battery, or with a completely dead one, and on the 65W adapter - most modern and semi-modern Thinkpads will limit CPU speed, and this is by design. However, since your battery is not dead, but "almost dead", I am not sure whether it applies.

One program, called ThrottleStop solved the issue, effectively bypassing it. Seems like Lenovo just coded the BIOS poorly. Never had such issues family's older Thinkpad - T41. This thinkpad now works with battery removed, because the battery is completely dead.

check ac power settings in bios are set to max performance - i the same behaviour on my t43 when i set them to energy saving.

wisdomkeeper wrote:One program, called ThrottleStop solved the issue, effectively bypassing it. Seems like Lenovo just coded the BIOS poorly. Never had such issues family's older Thinkpad - T41. This thinkpad now works with battery removed, because the battery is completely dead.

It's not poor coding - it's by design. Thinkpads are designed to throttle when running with a 65W PSU and no battery.

dr_st wrote:

wisdomkeeper wrote:One program, called ThrottleStop solved the issue, effectively bypassing it. Seems like Lenovo just coded the BIOS poorly. Never had such issues family's older Thinkpad - T41. This thinkpad now works with battery removed, because the battery is completely dead.

It's not poor coding - it's by design. Thinkpads are designed to throttle when running with a 65W PSU and no battery.

Be thankful, Dell machines throttle to minimum even if a battery is attached. It's strange an X200 would throttle with a 65W power supply though; that's generally limited to discrete graphics machines.

The bad/near-dead battery is to blame in this case.
Until you get a replacement battery, remove it so it can't damage your motherboard charging circuit.

RealBlackStuff wrote:The bad/near-dead battery is to blame in this case.
Until you get a replacement battery, remove it so it can't damage your motherboard charging circuit.

Any docs say why this happens?

Nope, just reading loads of times on various forums that bad/dying batteries caused charging circuits to get damaged.
Enough reason for me to abstain from/abhor bad/near-dead batteries.
My £0.01 (less than $0.02) only...

Dekks wrote: Any docs say why this happens?

Why? Well, one is essentially sending charge into an object that can't be charged and that current has to go *somewhere*...so pop goes the weasel or in this case, fuse...

Well, the battery is in condition to provide about 10 minutes of autonomous work.

ajkula66 wrote:

Dekks wrote: Any docs say why this happens?

Why? Well, one is essentially sending charge into an object that can't be charged and that current has to go *somewhere*...so pop goes the weasel or in this case, fuse...

so there is no "mechanism" in the charger to disable the changing effect in situations like this or when battery is charged fully?

There is. The recipient determines when to pull power. But if the failure is such that the battery cells are bad, yet the battery controller still thinks they need to be charged, all sorts of nasty things can happen. That's my guess.