After Effects 6.5
We did not have much time to test After Effects using our own in-house compositions, but we did run a simple AE Total Benchmark Test.
Comp 1 – Fractal Generation (shorter is better)

Comp 2 – Multi-layer compositing (shorter is better)

Although the 2x Opteron 252’s hold their ground on pure computation, when it comes to complex multilayer compositing, the newer Dual-Core Opterons are the fastest solution. Still, the differences were not as prominent as that with Bibble.
Canopus Procoder 2.0
We used a 21 second clip.
1440x1080p WMV-HD to 1920x1080p 24MBps MPEG-2 (shorter is better)

1440x1080p uncompressed HD to 1920x1080p 24MBps MPEG-2 (shorter is better)

Since the decoding of WMV-HD does not seem to take advantage of both CPUs, the performance gain from the Dual-Core AMD Opterons is virtually absent. That 1 sec difference is not likely to be statistically significant.
On the other hand in terms of strict MPEG-2 encoding performance, the new Dual Core Opterons are faster, but not by that much.