One of the reasons that the new Celeron performed so poorly, even when overclocked to the same speed, as the Pentium III (i.e. Celeron 850/100 vs Pentium III 850/100) was because the Celeron’s L2 cache featured a 4-way set associative mapping algorithm versus the Pentium III’s 8-way set associative L2 cache. The reason this discrepancy exists is because Intel essentially disables 1/2 of the L2 cache on the Pentium III in order to produce a Celeron (this can be confirmed by noting that the die sizes of the two chips are identical) and by doing that you essentially get half the “associativity”.