Intel Pentium II 300

This Pentium II 300 is fitted with the 'Deschutes'-core. It is the second generation Pentium II cores that is practically identical to it's predecessor 'Klamath' with the exception of the channel-width it has been built with. Deschutes is 250nm whereas Klamath is 350nm. The 250nm process needs less energy and obtains higher clockfrequencies. Most Pentium II 300's I see are based on the Klamath core. I guess when Deschutes was generally available most people bought 100MHz FSB Pentium II's that started at 350MHz.

Besides the change of the Klamath to the Deschutes core Intel also changed the L2-cache controller (L2-cache is not on-die is the Klamath nor Deschutes core but sits next to it inside the Pentium II cartridge). Differences can be found in the form of:
- 82459AB; original tag RAM chip for Klamath 233 to 300MHz. Only caches up to 512MB.
- 82459AC; found on the first Pentium II 333MHz. Still 512MB limit but clocks higher.
- 82459AD; found on the newer Pentium II's. Up to 4GB and able to clock higher.

Also the L2-cache changed with the introduction of Deschutes. Early Pentium II's have 6.5NS or 7NS cache chips that are fast enough to keep up with the lower clockfrequencies (remember, L2-cache runs at half the speed of the CPU). Faster Pentium II's had higher rated cache. I haven't openend my Pentium II 300 but there is a possibility that the L2-cache chips are higher rated than really is needed for 150MHz. This would make it great for overclocking. If it would have the late model tag RAM controller and would have high rated L2-cache chips it might be possible to increase the front-side-bus to 100MHz (instead of 66MHz) and run the CPU at 450MHz.