Max cacheable RAM on Gigabyte GA-5AX?

[Venerable]

I have a Gigabyte GA-5AX motherboard (ALi Aladdin V chipset) with 512k cache - how much RAM can the board cache? Will I see a performance decrease if I upgrade from 128 to 256Mb SDRAM?

The CPU is an AMD K6-III if this makes any difference.

Thanks for any response!

Justin B.