Failing laptop battery possibly leading to slow Windows 7 operation?

[othersteve]

Okay,

I know this sounds crazy, but I just had to post something about this to get some idea of whether or not it makes any sense at all.

Today, I had noticed that my laptop's video rendering speed was significantly slower than usual (1 hour, 20 minutes to complete a render that normally would take under 10 minutes). Simultaneously, I noticed that Windows 7 had suddenly started reporting that it was "not charging" the battery I had attached to the laptop. This wasn't just a Windows ACPI driver issue, either, as the computer issued a warning upon booting that the type of AC Adapter could not be determined.

After removing/reinstalling the battery a few times, I couldn't seem to solve the issue. I booted back into Windows and the rendering was still sluggish and the computer in general much slower than normal.

Finally, I shut down the PC and replaced it with a completely different battery. At this point, everything was perfectly normal--and the rendering time was once again under 10 minutes. The message upon booting also disappeared, and Windows 7 has no trouble charging the battery now.

My question is, does it even make sense that such an issue would slow the general performance of the PC even when plugged in? Because this most certainly seems to be what was occurring. Anyone else ever seen this before?

Thanks, and I hope you all had a Merry Christmas!

 

[Knightsman]

Is it maybe the performance being lowered by windows power plan?

 

[silvano]

It may be the AC adapter and not the battery. I've run into issues before where a failing ac adapter was enough to power on the machine, but not charge the battery and gave significant performance problems.

 

[othersteve]

It's odd, though, that swapping the battery for a different one was the only thing that appeared to correct the issue. It could be coincidence, but I had already tried powering off before, and even removing/reseating the battery!

The power plan isn't it; I've got everything set to High Performance on my PC.

 

[KompuKare]

Came across a similar problem once. That was in XP and was due to a bug in Microsoft's power management driver which constantly polls to see if the battery has gained / lost any charge. However, when the battery is bad this routine would seem to go into an endless loop of some kind and use up to 98% of CPU time. Process Explorer would list Hardware Interrupts at 90%+.

Microsoft had issued a fix for that but the fix did not work: ended up having to advise them either get a new battery or I'd 'solve' it for them by disabling the battery APM in device manager. That did work but it was hardly ideal.

Can't find the Microsoft KB atm, but I think they had tried to fix it twice and in this case (an Acer laptop) the fix did not work.

You'd think that Windows 7 would use totally different code for this (and I think that old Acer laptop did not even have ACPI) but with Microsoft anything is possible.

There's another bug to do with ACPI and USB mentioned here:
http://www.tomshardware.com/reviews/toms-hardware-uncovers-power-drain-issue,1835.html
and
http://forum.rightmark.org/topic.cgi?id=6:483
but for some strange reason that knowledgebase is not public at Microsoft's site. I smell a conspiracy of bad PM programming...

Anyway, do tell us if with the bad battery Process Explorer reports very high hardware interrupts.

 

[Knightsman]

Came across a similar problem once. That was in XP and was due to a bug in Microsoft's power management driver which constantly polls to see if the battery has gained / lost any charge. However, when the battery is bad this routine would seem to go into an endless loop of some kind and use up to 98% of CPU time. Process Explorer would list Hardware Interrupts at 90%+.

Microsoft had issued a fix for that but the fix did not work: ended up having to advise them either get a new battery or I'd 'solve' it for them by disabling the battery APM in device manager. That did work but it was hardly ideal.

Can't find the Microsoft KB atm, but I think they had tried to fix it twice and in this case (an Acer laptop) the fix did not work.

You'd think that Windows 7 would use totally different code for this (and I think that old Acer laptop did not even have ACPI) but with Microsoft anything is possible.

There's another bug to do with ACPI and USB mentioned here:
http://www.tomshardware.com/reviews/toms-hardware-uncovers-power-drain-issue,1835.html
and
http://forum.rightmark.org/topic.cgi?id=6:483
but for some strange reason that knowledgebase is not public at Microsoft's site. I smell a conspiracy of bad PM programming...

Anyway, do tell us if with the bad battery Process Explorer reports very high hardware interrupts.

Good to know, thanks!