On my Celeron 935 (overclocked) running in WinXP, I could encode at about 2x with LAME 3.89. With LAME 3.91 it's about 4x. With 3.89 I was using the individual parameters recommended by www.r3mix.net. With 3.91 I use the --r3mix setting which uses the faster VBR algorithm.

I just upgraded my HTPC to a P4 1.6A running at 2.1 Ghz. I've got to try some encoding on that machine. I bet it'll scream.

-Dylan