Could you post a high res picture of the motherboard? Or at least a model?

ASUS is pretty old. Here is one of their 386 motherboards I have waiting in queue for repair.

There are Chinese sellers that usually have them for pretty cheap. Find out how much cache that board can take and then go from there.

You will want ones rated at 15ns (-15) or faster though the ones labeled faster than -15 are probably relabeled -15 chips.

You will also need the tag chip which may be a different length depending on the board and what size the regular cache chips are that you get.

What is the model of the motherboard?

cyclone3d wrote on 2025-03-10, 05:12:

There are Chinese sellers that usually have them for pretty cheap. Find out how much cache that board can take and then go from […]
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There are Chinese sellers that usually have them for pretty cheap. Find out how much cache that board can take and then go from there.

You will want ones rated at 15ns (-15) or faster though the ones labeled faster than -15 are probably relabeled -15 chips.

You will also need the tag chip which may be a different length depending on the board and what size the regular cache chips are that you get.

What is the model of the motherboard?

correct, from what i read many motherboards (486) sometimes give 2 options 128 or 256 cache, and you need different combinations for tag.
i think for example if you want 256 cache installed you need the same tag chip markings as the rest of the other 8 chips

the motherboard is ASUS VL/I-486SV2GX4

these seem to be more available on ebay: w24257ak-15 would those work good?

The manual is available here:
https://theretroweb.com/motherboard/manual/31793.pdf

That board can take up to 1MB cache.

Search on eBay for:
sram dip

Then look for the 10pc sets of the 512k and 1024k chips.
Looks like 512Kb would be around $12 and 1MB would be about $32.

Also,
I would verify the board works before ordering cache for it.

cyclone3d wrote on 2025-03-10, 06:01:

The manual is available here: https://theretroweb.com/motherboard/manual/31793.pdf […]
Show full quote

The manual is available here:
https://theretroweb.com/motherboard/manual/31793.pdf

That board can take up to 1MB cache.

Search on eBay for:
sram dip

Then look for the 10pc sets of the 512k and 1024k chips.
Looks like 512Kb would be around $12 and 1MB would be about $32.

Also,
I would verify the board works before ordering cache for it.

will do
but 512 cache or 1mb cache isn´t that overkill?
you get amazing performance boost from 256 to 1mb?

256k cache will probably be enough.

The size of the cache determines how much RAM is cacheable.

The board max is 64MB, for which 512k cache is needed for WB operation and 256k for WT.

I have one of those boards since new, they came out with 128k cache. I haven't upgraded mine, it is currently running 24MB RAM.

Can you get a set of 256k 15ns chips for less than $12 shipped?

I like maxing out the boards I have, especially when they have none or less max cacheable or slower than 15ns.

No real reason not to with the prices being that low.

When I received the two boards that I have, they already had cache modules installed but I think the previous owner just installed modules from other boards that he had without paying any attention to the amount of cache that the boards support.

Both boards boot and seem to operate just fine but please help me understand whether this cache setup makes any sense:

Gigabyte GA-486AM/S Ver 2.20. (First pic below)

4x UM61256FK-15
1x AE88128AK-15

Gigabyte GA-5486AL Rev. 2A. (Second pic below)

4x UM61512AK-15
1x UM61 256K-15

byte_76 wrote on 2025-03-10, 17:00:

When I received the two boards that I have, they already had cache modules installed but I think the previous owner just install […]
Show full quote

When I received the two boards that I have, they already had cache modules installed but I think the previous owner just installed modules from other boards that he had without paying any attention to the amount of cache that the boards support.

Both boards boot and seem to operate just fine but please help me understand whether this cache setup makes any sense:

Gigabyte GA-486AM/S Ver 2.20. (First pic below)

4x UM61256FK-15
1x AE88128AK-15

Gigabyte GA-5486AL Rev. 2A. (Second pic below)

4x UM61512AK-15
1x UM61 256K-15

1. 4x 32kx8 = 128k, required tag 8kx8, chip present, 16kx8 which would allow both banks to be filled for 256k
2. 4x 64kx8 = 256k, required tag 16kx8, chip fitted 32kx8

PS. for the original question, this looks an ok set https://vi.aliexpress.com/item/1005006752389377.html - 10 of the 64kx8 - to stuff both banks for 512k and can probably use one of them in TAG as well

Be careful as the Aster tag has a different pinout. Boards supporting it will have a jumper to switch between Aster and standard pinout.