super pi calculates the decimals of pi to selected lengths, 1 million is the standard test just about everyone uses, and sometimes 32m
IIRC a clocked A64 takes ~30sec for 1m and a clocked c2d should get sub 20's (don't quote me on that one though) I'm not sure how long 32m takes, but it should be 15min or so
http://files.extremeoverclocking.com/file.php?f=36