So, the hyper-threading technology does not work well in Bryce application. In that case, why Microsoft did not create a processor with real multi-cores (8-16-32 ...)? We pay real money for virtual processors, and we do not get a large increase in productivity for our 3D creative works. It’s very sad. :-(
I would say it works as well as can be expected given the resources available. Rendering is one of the few 100% processor intensive applications that I can think of. Games for example use around 80%, this leaves some headroom for other applications to take advantage of virtual cores and run processors in the background.