This sim is extrememly processor intensive and I suggest limiting other programs from running while the sim runs. When you switch focus you cut the data stream from the network and the client doesn't know what to do.
There is a misnomer in the general lands of consumer processing about "threads". On a single processor it takes more time to run 2 threads than it does one doing 2 different tasks. I.E. you have a thread that calculates some value. That thread runs for say 10 mili seconds then it has to do a thread switch so other processes can run. To do the switch, the state of the machine needs to be saved, all registers and instruciton pointers, stacks, all needs to be stored. So the processor has to stop what it is doing, store it's state, get a different thread state, load it up and process the second thread. If you are good with the code you can have 2 different processes accomplish the same task faster in a single thread. Multi Core is a different issue and it will allow 2 things to run at the same time or in parallel.
I may be switching to a different engine in the near future so just bear with this for the time being. Good question.
