CPU
From xboxdevwiki
The CPU in the Xbox was a custom Pentium 3 running at 733MHz. The 'custom' part of this was that that the Pentium 3 in the Xbox was that it had only 128KB L2 cache instead of the usual 256KB. This allowed Microsoft to buy them at a bit of a discount and Intel to shift a few more CPUs[citation needed].
References
- Mobile Intel® Celeron® Processor (0.18μ) in BGA2 and Micro-PGA2 Packages (This datasheet is for the mobile version Coppermine with 256kB L2 cache. It does not contain the Xbox Coppermine-128 with 128kB L2 cache at 733MHz (S-Spec SL5SN). No such datasheet exists. Both differences are pin compatible.