Any of them would benefit from faster/more efficient processing, but most users would recommend against multitasking during the encoding process...
I use DVD-Rebuilder with CCE on a dual P3 850 system running Win2k, and the processor load gets split pretty evenly between both processors; I usually get about 80% CPU load in task manager when CCE is encoding. I multitask during encodes with no problem, since there is still unused CPU load. Since my encodes have been taking around 10-14 hrs (Babylon 5 series), I pretty much have to multitask if I want to get anything else done. On my wife's Celeron 1100 system however, if I try to run DVD-RB, it takes up about 90% of the CPU and pretty much locks it up; can't do anything else until the encoding finishes.
