"Indeed AthlonXP doesn't yet support SSE2. (Next generation CPU will) But although the performance pack is called a P4 pack, the explanation about it only talks about SSE and talks about improving the P4 AND P3." I guess until we get some comparative benchmarks we are at a stand still on this - guessing about code we can't see :) "So it's not the disk that is holding things back. It's not the CPU nor the amount of memory. What's left?" A good question! I am curious why a scene with 2 mil figures (Vick and Steph) and complex hair with a UD light setup renders faster (MUCH faster) than that benchmark did. Maybe a second benchmark file is needed to compare another data point?