FWIW, on a dual 275, it's roughly 4x realtime, CPUs are bouncing between 90 and 100%
On my laptop, 3.6GHz, it's roughl 12x, CPU slammed.
compressed to compressed anything tends to be pretty hard on the system, but the performance is still pretty impressive. Just for giggles, tried this using Procoder, and it was only slightly faster, and has a line on top/bottom like a tossed field or something. Also has some ringing on the edges. So, faster, but not quite as good in some ways. Just a tad cleaner on the high contrasted edges.
I gotta start saving up for a Dual Opteron workstation, thinking about switching to HD production this winter. Hopefully the CPU (and mobo!) prices will be down a bit by then.
Then I'll double dare your double dual core!
In fact, I'll double dare you to a double dual core duel! :O) :O)