Take computational load off the IRC controller and use a desktop PC instead for high cost task

When the IRC is running in automode and the program is triggered (press F8) in robotstudio, what actually goes on in the background?

Does the PC run through the programs and perform whatever calculations there, prior to sending information to the IRC? Or is the program just dumped over wholesale and the IRC gets to struggle with the massive computations? I believe many would notice that the processor on the IRC is far from good and cant really handle too much. 

How can we get it running smoother?