They are talking about that in this thread: Re: AMD K6 3DMARK, aiming for stars.

I don't see much value in it as other people. The VIA chipset onboard cache is really for CPUs that don't have L2 cache like the original K6s so its there for those cpus. THe mobile CPUs L2 cache can cache probably like 2gb of ram and they don't need it and u can just disable it if you have one of those. Leaving it enabled has shown barely any speed improvments for + versions, and I tend to believe that cache is probably slower than the cpus cache. Generally the onboard cache can only cache 128mb for 1024 and 256 if u have 2mb, but there is no limitation for Plus cpus.

First thing I do is disable it. For me challenge of socket7 is how slow can you make it go, not how fast.

Warlord wrote on 2020-07-22, 02:52:

[...] and I tend to believe that cache is probably slower than the cpus cache. [...]

It is. The board's cache runs at fsb frequency, while the CPU's cache runs at the CPU's clock frequency.
Technically the board's cache becomes L3 cache when using a cpu with an onboard l2 cache.

I've been playing with my fastest ever Socket 7 setup: a Soyo 5EMA+, a K6-2+ 550 (currently at 5x124) 256 megs of PC133, a Radeon 9200, and a Sound Blaster 16 CT4170. The onboard cache won't work at 124 MHz, and has to be disabled. Whatever advantage it may give at lower bus speeds is more than made up for by higher clock speed and more memory bandwidth from the greater bus speed.

I also have an Asus TXP4 with a K6-3+ 450 at 500, and my 3D Mark score improved by nearly 200 points by disabling the L2 cache. It can only cache 64 megs, and I have 256 installed, so it's more of a hindrance than a help.

I haven't used it yet, but I've got an FIC VA-503+ that has 1024kb cache instead of the normal 512kb on an MVP3 chipset board, like the Shuttle-HOT591p i'm running now. technically upgraded? you decide. i think 128mb ram is still a tonne for this system and 256mb is overkill too.

There are a few other SS7 boards with 1024kb L2 cache but GL finding them.

https://www.anandtech.com/show/123 here's one that looks promising.