Strange fan behaviour - can anyone explain this?

I have a HP Elitebook 8760w that behaves very strangely:

When playing a 1080p movie via displayport to my TV the fan will go loud after few minutes when using the power cord.

If I play the same 1080p movie via displayport to my TV using just the battery, the fan stays low at all times.

Please note:

All power plans (balanced, power saver and high performance) are all exactly the same, just to make sure.
In all power plans I have the same settings, so when using the power cord it should behave the same as the battery.

The graphic card is an AMD FirePro M5950.

Thanks

 

I think there is a cooling state policy in the power settings, generally for all windows profiles, on battery it will be set to 'passive' whilst on power it will be on 'active'. Just need to change that setting when you want it to be quiet.

 

Yes, the system cooling policy is passive in all Power Plans

 

Do your temps jump with the fans running lower on battery power?

 

No, on battery power everything is fine, the fans will even stop when only doing light office work.

 

I call attention to the power adapter then. See if you get the same results from a replacement or compatible universal adapter.

If you do, then it might be the jack or a circuit on the board. Sounds a bit like overvolting.

 

Ok, I will contact HP about this.

Thanks

 

what the problem might be is that unpluged you run on diffrent settings. Usualy powersaving which means less power -> less heat. So when pluged in your laptop will make more heat making the fans turn on. Dont know if this is the case but it could be an explanation

 

There may be a hardware profile in the mother board that over rides that. I know on my 5920G the fan control and profile is hardware driven and it can not be accessed or seen by speed fan.