Pentium (P5, P54) has 16KB L1 cache. It's a split L1 cache, 8KB for instructions and 8KB for data. Pentium MMX (P55C) has 32KB, split in the same way. This is where most of Pentium MMX's performance improvement came from; double-size L1 cache.
Pentium Pro has 16KB L1, and 256KB to 1MB L2 in the other package cavity next to the CPU die.
Pentium II gets the 32KB L1 cache like Pentium MMX, but it loses the fast cache memory. Luckily they doubled the L2 size though (compared to the popular 256KB PPRO). And MMX. This makes it much better for gaming than PPro, IMO.
PPro is actually going to be at somewhat of a disadvantage to PMMX in some games. MMX is used occasionally. Unreal won't let you have high quality audio without it, for example. Unreal's software renderer is heavily optimized for MMX, too. I've messed a lot with a PPRO 1MB in the past couple years. I actually have one or two PPRO 1MB CPUs that will overclock to 233 MHz.
Any of these CPUs is fine for DOS though. A 200MHz Pentium is probably more than adequate for just about any DOS game. Pentium MMX 233 MHz (the top) is probably the sweet spot, or something, 🤣.