Nowdays both ATI and NVIDIA have techniques for lowering the GPU power consumption in notebooks based on lower core and memory speeds in 2D modes or while running the notebook in battery mode. While NVIDIA uses their Powermizer integration in Windows Power schemes (2D mode in Power saver, Low power 3D in Balanced and High performance 3D in High performance), ATI have their PowerPlay running in any of the Windows power modes as user directs it. For us Power Play always seemed the smarter and more controllable function, yet it doesn’t always do what it has to. For example, if your notebook has Mobility Radeon HD4570, it may suffer from a bug in PowerPlay that can lead to lowered memory speed in both power saver and performance modes. There is a fix, though.
We found that most Acer notebooks that use HD4570 with DDR3 memory run the card core at normal speeds, but they don’t control well the VGA memory speed and it stays at 500 MHz mark all the time – even in 3D modes like games or high quality video playback. Tools like GPU-Z happen to show the default mode as 800MHz (1600 MHz DDR), but current speed is always 500 MHz. According to that article in 3D Vision Blog, to fix that, you only need to disable PowerPlay in Catalyst Control Center. Which is kind of awkward, as the card will draw more current while you are on batteries, yet it’s desirable change, as HD4570 has 64-bit memory bus and memory speed is critical for its performance.
It’s a VBIOS problem, so we doubt that ATI would fix this, especially as their Mobility Radeon drivers are only available for Windows 7. BTW – it changes cards performance dramatically – like over 30% in most 3D modes!
10/10 for both ATI and Acer. It’s not a bug, but a dealbraker if you want to play games.
Higher Twisted Rating is worse!
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