If you want MP3s and use out_lame it will be faster than real-time.

If you want WAVs and use Output Stacker with waveout+diskwriter, it will be real time, because waveout is involved. But I think the only reason the original hint requires waveout is because diskwriter can't be first in the stacker list for some reason - it needs something before it. You could probably use a visualisation plug-in. In that case, it should be faster than real-time.