Are you using AFNI now, or just inquiring about it? 3dvolreg for motion correction is pretty fast - it was originally designed to run in realtime, in fact. AFNI doesn't usually do spatial or temporal smoothing - these are SPM constructs. Deconvolution can be slow, but is still usually faster than the actual data acquisition - in fact, we are thinking of implementing deconvolution into the AFNI realtime acquisition plugin.
bob cox