Office Application Benchmark
Duron still shines against Celeron even if both are overclocked! A Duron 900 is already faster than one of the rare Celeron 1 GHz in Sysmark 2000. Thunderbird may not be quite as fast as Pentium III on a Solano platform, but a 1 GHz Thunderbird at 1050 MHz can already skip the GHz Pentium III, which is virtually unoverclockable.
3D Gaming Benchmark
In Quake 3 Arena the picture looks even better for Duron. Once the little AMD processor is overclocked to 850 MHz, which should be possible with any Duron, it can top a Celeron overclocked to 1 GHz! Thunderbird needs the 1050 MHz once more to leave Pentium III 1 GHz behind. However, please be aware of the fact that it is virtually impossible to overclock Coppermine over 1 GHz right now.