Hi John,
I'm delighted Oxygen works with Ubuntu crossover. I don't have a good benchmark test yet but I'm putting some performance metrics into the OpenGl Edit control. It uses almost no CPU except when the screen changes then it gets very busy and uses at least one core to capacity. Each frame takes about 14-17 ms to process.
I would not expect to see a major difference under Ubuntu - give or take 10%. It uses very basic API calls.
Charles