v8+crankshaft (available in recent canary builds) is ... fast. really fast.
on my machine, both @640x512px+aa:
chrome 9: ~30 sec chrome 11: ~16 sec ff4b10: ~47 sec
my own simulated annealing image whatever: this one was always a stronghold of firefox's tracing JIT, because the fitness function consisted of dumb looping over a huge array just summing up values and (i assume) the tracing approach worked very well here.
lower is better:
chrome 9: ~50 ms/gen chrome 11: ~17 ms/gen ff4b10: ~22 ms/gen
v8+crankshaft beats jm!
this is very, very nice. especially for long running apps - think what it will do for node.js!
disclaimer: no real, serious testing was done, just fooling around. but try it and see for yourself!