Strange 8740w BSODs - only on battery

After months of trying I have been unable to resolve this issue with a 8740w (i5-520, FirePro, Win7 64) that I bought second-hand. About one in every two-three times I boot into Windows on battery (without a connected charger) I get one of the following problems:

- BSOD right before or right after the desktop appears;
- BSOD with a very dark screen right before or right after the desktop appears (a boot to black of sorts, although the screen image is somewhat distinguishable);
- minor screen corruption (similar to bad videocard memory symptoms), which also appears frequently when I resume from sleep.

This being said:

- None of these symptoms ever occurred on booting with the charger connected;
- If the computer booted fine on battery (about every other attempt), no BSOD appeared subsequently (but the battery is only good for about 1,5h, so I could not test more);
- As long as I booted on the charger, I encountered no other errors of any kind whatsoever, not even during stress-testing (prime+furmark), day-long gaming sessions, other stressful software (AutoCAD), or plain work;
- Windows dump files identify all manner of errors, usually connected to a Win7 kernel file (in other words, the error identifier is shooting in the dark).

Things that DIDN'T change this behavior:

- Frequently taking the battery out and pressing for 1 minute the power button did not seem to have any effect.
- The memory is not the culprit (the Elitebook passes memtest several times and I have changed both dimms anyway, since mem is cheap, just to be sure).
- Reinstalling Windows 7 with a minimal set of drivers did not solve the issue.
- I have tried all possible FirePro drivers, from those provided on the HP website, to those provided for HP specifically by AMD, to generic R5800 series, to all of the above without CCC - yet the symptoms remain.
- Replacing the charger with a 230W one did not change anything (and the Elitebook came with the newer, problem-free version of the 200W brick anyway).
- Changing the bios several times between F.21 (the bios I bought it with) and F.20 left the matter unresolved.
- Playing with bios settings (enabling/disabling things like Power Circuit, Turbo Boost, all the 'Quick' HP options, USB charging and several others) seemed irrelevant for my problem.
- Charging the notebook through a docking station did not help either.

Short of spending 100$ on a battery (which I am not eager to do since I am skeptical this is the problem - the battery is fine otherwise, and only has some 8% wear level), does anyone have anything to suggest?

Thanks in advance!

 

Something to try: disable the ATI video card in device manager, and then boot with the charger disconnected. That should tell you if it's video-related.
(It'll also likely jumble up your desktop icons, though.)

 

Good suggestion. I'll do that. Back in a few days with details.

 

I used it for 2 days without the ATI driver. No problem encountered.

Strange, because I have never had any vidcard issues with the notebook plugged in.

Suggestions?

 

I have some more feedback with booting on battery (& recovery from sleep) problems, both of which seemed M7820-related and induced partly similar behavior.

While testing without AMD drivers installed, and encountering no problems whatsoever, I realized that the GPU was running at maximum speed. It was a serendipitous finding: I noticed the fan was spinning faster more often, so I checked with GPUz, which reported max speed on both memory and processor (as expected, in fact).

So I thought it might be a good idea to install the driver but disable Powerplay in CCC and see if I keep getting the annoying boot-on-battery and sleep issues. So far, after almost 3 days, everything has been running smoothly - it's enough to indicate a solution has been found eventually, as long as you accept the no-powerplay trade-off.