I have a HP DV7 notebook which came with Windows7 Home and everything worked really well on it. I then installed my original copy of Win7 Enterprise (which I bought thru work) and found that when I unplug the notebook from the power brick, it starts to slow down to the point where it becomes unsuable.
I've checked the CPU speed and that does not change, the memory & HDD was tested by an HP technician and nothing was found wrong. When I plug the power back in, the notebook starts running as quick as it should so really I can only use it while it is plugged into power which is not the ideal situation with any notebook.
If I run it in Safe Mode it works great with or without power so it must be something to do with a Windows driver. The HP technician was dumb founded and suggested that I reload the original Win7 Home and leave it that way. I did not want this to be the resolution so I'm asking you guys if you can help me.
I re-installed Win7 Enterprise (a few times!) and as soon as I finished installing Win7, it slows down when power is unplugged. I then installed all the drivers using the HP Support Assistant and SP1 and it still does the same thing. It has me baffled.
Install W7 Home and the do a W7 Ent upgrade over the top, will keep the power settings.
It's a bit late now- I've had the OS running for two months now with the same issue. I can't go back to the factory install and then upgrade- it's too painful.
What I would really love is to understand what is going on and which driver is the issue. It's not BIOS related as I checked there and there are virtually no settings to change except for the standard ones.
Here's the PerfMon graph for ProcessorInformation including the following counters:
1. Processor Frequency
2. % of Maximum Frequency
3. % Processor Time
As you can see on the right, power is plugged in and the processors are running at their max performance. On the left is where I unplugged the power and the notebook switches to battery power. You can see the Processor Frequency drop from 1734 to 111, the % of Max Frequency drop from 100 to 6% and the % Processor Time of each processor jumps up as the first two counters go down.
I would thus assume that this is the result of unplugging the power on the notebook, but now the question is WHY?
Go to control panel> system> power options
Select high performance if its not already selected like you say.
Now click Change Plan Settings
Followed by Change Advanced Settings
Click Restore Plan Settings
Click the +sign next to Processor Power Management.
Click the + next to Minimum Processor state. Battery defaults to 5% with AC set to 100%. Since this is the minimum state just verify these are correct.
Click the + next to Maximum Processor state. Both should now be set to 100%
Now reboot and see if your performance is what it should be. If not go back in and check to see if those setting have changed. HP had a power management driver which was flaky but I thought they fixed it. You can unistall it if you did install it.
You know what? I found the solution and it was staring me in the face all the time. Have a look at my post above, the one with the two images. Look at the second image.
I found that if I change the "System Cooling Policy" for Battery from Passive to Active, IT WORKS!!!!
So with this one setting changed, when I unplug the notebook from the power brick, the notebook runs like a dream and does NOT slow down anymore.
PS. Not sure if this is related, but my notebook is now overheating. It's running idle at 80 deg C and hits 95 deg C when transcoding video. I blew out the air vents with a compressor and that dropped the temp back to 70 deg C idle but I feel there is still an issue with overheating so i decided to send it in to HP to get a service.
In Summary, HP Home IT Support are useless in finding technical issues. Their last line is always "Well, it works with the factory OS" but who buys a $2K notebook to keep the factory OS on there?? Thanks everyone in helping out. I'm so happy to have fixed this issue coz a notebook is not a notebook unless it can run OK on batteries, true?