I recently bought a Samsung Ativ Book 8, which has a AMD Radeon HD 8870M GPU with 2 GB GDDR5.
It has AMD catalyst installed to manage switching between GPU's for different apps/power usages. I put all options AMD Catalyst on high performance, and also set Chrome to run in High performance mode.
Though when I run a simple WebGL demo (like the Chrome Aquarium demo) I get about 20 Fps on medium settings (not very good). I then downloaded GPU-Z and noticed that indeed the CPU load of the Intel HD 4000 was quite high when running this demo, and the Radeon seems inactive.
When I run a game it does show a high GPU Core Clock for the Radeon, so that seems to work just fine. Also Samsung installed a handy update tool, which updated all the drivers recently, so that shouldnt be a problem.
Chromes setting "use hardware acceleration" is on. A webgl demo in firefox was also using the internal Intel GPU.
When I disable the internal GPU through windows decive manager, windows falls back to the "Microsoft basic display driver" instead of going through the discrete GPU.(not sure if thats normal?)
I installed FurMark (GPU testing app) and when I click on GPU Shark (with both GPU's enabled) I get the following output:
Current graphics drivers not supported Trying to load available information... - Graphics card: Intel HD Graphics 4000 (M) - Graphics driver: 184.108.40.20663 (1-16-2013) - GL:atig6pxx.dll - GPI: IvyBridge(GT2) - BIOS: Intel Video BIOS - Unified shader cores: 16 - TPD: 35W - Memory size: -1984MB - Device ID: 80860166 - OpenGL renderer: AMD Radeon HD 8800M Series OpenGL 4.2.11932 Compatibility Profile Context with 238 extionsions - GLSL 4.20 - OpenCL OpenCL 1.1
Any idea how I can run Webgl things over the discrete GPU?