There is a small, but measurable improvement going from 256 to 512. I want to say something like 1-5%.

It depends more on how much RAM your machine is running. If you have enough L2 cache to cache all your ram, you should be fine. Increasing the amount of L2 cache won't have any noticeable impact on performance, but using too little cache or to much ram can cause your machine to slow-down.

So what is the ram limit for 256kb cache or does it depend on the size of the tag chip?
I could put either 64Mb or 96Mb of ram on the motherboard. I have 2x32Mb edo ram modules and 2x16Mb edo ram modules.

Max cacheable ram on intel socket7 chipsets is 64mb (intel 430FX, 430VX and 430TX). Only exception is the 430HX which can do a lot more depending on the amount of cache.

I suppose even 64Mb is bit too much for a pentium system. I only had 16mb in my pentium system that I bought back in 1995 with win95.
If I use 64Mb of ram, do I need 512Kb of cache for it?

Phil did some cache tests in one of his 486 videos. Can't remember which one, though. Here they are if you want to look for it:
https://www.youtube.com/playlist?list=PL5T8bm … XxdDdMJ8MokDwSq

kanecvr wrote:

It depends more on how much RAM your machine is running. If you have enough L2 cache to cache all your ram, you should be fine. Increasing the amount of L2 cache won't have any noticeable impact on performance, but using too little cache or to much ram can cause your machine to slow-down.

Cache size does matter. Bigger cache means more buffering of the data CPU is processing.

Simple: bigger cache = better performance.