AnandTech has tested the new GPU acceleration of Flash Player 10.1 beta, you can check out the benchmarks over here.
Anand reports he saw big improvements in average CPU utilization on a system with NVIDIA ION graphics, but on an AMD 785G system with integrated Radeon HD 3200 graphics the performance did not go up, in many cases it worsened.
Drivers seem to be the culprit, Anand received a new set of drivers from AMD but they were no good either as they don't seem to enable H.264 decode acceleration under Hulu. He also noticed some issues with the Intel GMA 4500MHD, and expects this is one of the areas Adobe will work on during the next couple of months prior to the official launch of Flash Player 10.1.
So while Intel and ATI users need to wait a bit longer, users of low-power systems with NVIDIA graphics may do well to check out the pre-release version today. Anand did some testing on an ION netbook and says 720p HD flash video runs butter smooth with Flash 10.1.