I don't know about 612 kb L2 cache (did you meant to type 512?)...
Anyways.... the Athlon will win the match. However, it would also depend on what kind of Athlon it would be... like if it's one of the older versions of Athlons (32-bit), then the benchies may come out to be about the same.
However, from the surface point of view, it seems that the Athlon is more likely to win the match w/ the Celeron.