Someone can fix me if I'm wrong, but as far as I know there is no hardware acceleration, and it really wouldn't even help, Darwinbots is very much CPU bound.
As for why you are running so slow, there are two buttons that can speed it up some, Fast Mode, and Flicker Mode, (Green arrows on the toolbar). For me on windows Vista x64 I get up over 2000 cycles/second with <40 bots and it scales down from there (With fast and flicker)
Which bots are you running?