On full power why unplugging reduce performance?

[mjmattson]

Okay, this is a strange one (at least to me). I have a M200, 2.0GHz and have the Toshiba power settings set to default full power when plugged in and when unplugged. I have an application that runs perfectly fine when it is plugged in, but if I unplug it it seems the performance of the tablet drops.

How do you guys tell if your processor speed dropped? I can run SIW and it tells me the processor is at step 6 both plugged in and unplugged, but there is a noticable drop in performance?

Any ideas? I know it is in full power both plugged and unplugged. Processor set to fixed - 10 with max cooling.

If I change to Windows "Always On" power setting it does the same thing?

Any ideas?

Thanks,
Matt

[WNewquay]

Hi Matt,

Just a shot in the dark.

If you start the application on battery and then plug in the power, does the performance improve?

Could the difference in screen intensity be altering your perception of performanc?

[mjmattson]

No, it is definitely a slowdown in performance. The screen intensity does not change at all...it is max brightness.

It seems that something slows down the tablet when off AC power, but there does not look like there is an app running taking CPU, etc.

This happens regardless of whether I use the Toshiba Power Saver or Windows "Always On" power settings.

[mjmattson]

Update:

I found that if I drop the system color quality from 32-bit to 16-bit it seems there is no difference in performance from using AC power or battery. If I put it back on 32-bit...there is a system slowdown on battery power and NOT on AC power.

Strange. Is this a video driver issue? Does the system realize it is on Battery and operate differently? We can adjust brightness, but I wonder if the video hardware knows the difference and lowers performance if on battery.

Anyone have ideas on that?

[sneezinglion]

It could be the video card is going into low power mode on battery. Check your nvidia control panel and look for power settings. I think it defaults to low power on battery.

[mjmattson]

That was it! I found the "Power Mizer" setting and bumped it up to full performance on battery.

Thanks for the help!