A little mistake, some missing data, and an information...
- 386DX were actually the first processors to have L2 cache: a 386DX20 sold in an Amstrad could be found with 64K of L2 cache; the 386LX was a SX with support for the HLT instruction (stop CPU on idle).
- the 286 was interesting because, due to a bug, you could re-route a part of the BIOS address range to RAM, allowing you to keep some code in the executable memory range (and go past the 640 Kb barrier); this came to be called "high memory", and was used to host device drivers like mouse, VESA.
- the Pentium, not in charge of its L2 cache, relied upon the chipset to manage cache and memory; the most efficient Intel chipset was the 430TX (it supported FPM DRAM, EDO DRAM and SDRAM, and USB), which couldn't cache memory addresses above 64 Mb. You could install more than 64 Mb, but performance would degrade greatly.
- The Celeron 300A overclocked reliably, but more than anything when doing so it outperformed Intel's then-top Pentium II 450 MHz, which ran with a 4x bigger but half-speed L2 cache making the 300A@450 better for 3D games (which enjoyed low latency over size) especially when combined with the 440BX's stellar efficiency memory-wise and some low-latency SDRAM.