FUD Zilla writes AMD will use Havok to accelerate physics on the processor, the site says AMD has no plans at this point to do the same trick on the GPU and speculates Intel may not even allow AMD to do this:
Common sense is telling us that running Havoc on a GPU should be much faster as Shaders are independent pipelines or cores and you have quite a lot of them on a modern GPU.
ATI says that it plans to accelerate Havoc on a CPU while for the time being ATI says that it will also investigate if it makes sense to run Physics on a GPU and that it will do it when it makes sense. This probably has a lot to do with a fact that Intel owns Havoc, but doesn't really have a GPU to run physics on.
To spice up this already complicated story, sources close to Nvidia believe that Havoc will only be accelerated on Larrabee graphics parts and that ATI will never get a license to do Havoc physics on its GPUs. We cannot confirm or deny this claim but it sounds like a good conspiracy theory.