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I have an AHTEC Sense XHLB2 (a relabeled version of the Compal HLB2) that has a VGA ATI Radeon HD 4650.

When I switch off the power plug and run into battery mode the perfomance of the laptop is severely affected. After running some benchmarks I found that the VGA results are something between 35% and 200% slower.

How can I avoid the change of the VGA performance even If this makes my battery life shorter?

EDIT: Changed typo from 6450 to 4650.

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Without benchmarks, you can check with GPU-Z (techpowerup.com/gpuz) also, which will show you the actual reason, which is that frequencies of gpu and its memory are decreased in battery mode. – Gnoupi Jan 17 '10 at 11:02
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6450? Have I missed a generation? Last time I checked we were still in the 5000 family. – alex Jan 17 '10 at 11:23
@alex - I'm guessing he meant 4650, he should probably edit it to the correct version. However I don't think this changes the performance problem. – Gnoupi Jan 17 '10 at 11:52
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ATI graphical cards on laptops are relying on the PowerPlay "technology".

It adjusts the frequencies from the GPU and its memory, to save power. You can deactivate this option in the Catalyst control center which should be installed with your drivers:

powerplay options

If you deactivate it simply, the card will be on maximum performance all the time. You can also enable it, and choose yourself which performance level should be used depending on the power status (if I remember good, there is also an intermediate step between max and min, on ATI power management, which could be eventually enough for some programs, and would allow to save power compared to the maximum, in battery mode).

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Ok, I will give it a try. I just installed the driver. I usually hate all the software that comes with the drivers. Usually they give more trouble than anything. – SoMoS Jan 17 '10 at 18:25
Mmm, I do not want to install the CCC. Is there a way of deactivating PowerPlay writting something at the registry or something like that? – SoMoS Jan 18 '10 at 15:16
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@SoMos - I know that Notebook Hardware Control (pbus-167.com) allows you the same kind of control over your ATI gpu frequency, depending on battery level. It takes place only if powerplay is off, leading me to think it can work without the CCC. But it is another layer to install either way. Anyway, that means it is possible probably to do, but I don't know how, sorry. – Gnoupi Jan 18 '10 at 15:21
anyway its a good starting point to check. I do not want to install almost anything at the host as I do pretty everything on Virtual Machines. CCC requires Framework and I do not want to install it. – SoMoS Jan 18 '10 at 20:53
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