vim: how to make split window "run" in parallel

not sure this should be a vim issue or ConqueTerm plugin issue, I guess essentially it is vim.
so with ConqueTerm I'm able to open multiple buffers and run a bash from inside each buffer.
each bash I may run a info-collection-script that takes long time and lengthy output before finish.
for easy comparison, I even use "vnew" so I have 2 vertial windows running 2 bash in parallel.

now, the interesting thing I found out of this method is:
whenever I switch window (changing focus to another window),
the output from the previous window (that just lost the focus), got hanged there,
until I move focus back to it.

is this per vim design, or there is a workaround/knobs, to make 2 buffer run in parallel?

regards
ping