ISSI IS61C1024-15N chips are probably the easiest to source. They're available in 15, 12 and 10 ns ratings - in theory. No matter what they say, most if not all of the Asian sources selling the faster ratings only ship the 15ns part.

Also, when ordering cache chips, you should have a plan for dealing with failed parts. I've done two boards with these ISSI chips from two different sellers and haven't had a bad one yet, but it's best to assume the risk that some percentage of them will either be dead or unreliable under testing.

15ns are good enough as they are rated up to 66MHz operation (FSB).

what about price. how much approx does it cost to get a set of 1mb? (8 chips x ??kb?)

chrisNova777 wrote:

http://www.amoretro.de/ebay/2013/06/vli486sv2gx4_1.jpg
im not sure if the chips in this pic equal up to 1mb or not otherwise
id just copy the names from the image!

That is not 1024kb cache

You'll get around 2-5% extra performance with maxing out the cache.

Firage is right. It's probably cheapest to buy them from Aliexpress:
http://www.aliexpress.com/item/Free-shipping- … 6e-aefbf9e84627

kixs wrote:

15ns are good enough as they are rated up to 66MHz operation (FSB).

The SiS 85C471 chipset documentation (download/file.php?id=12284) has a table on pages 8-9 that recommends 12 ns cache SRAM at 2T-2T-2T or faster timings @ 40 MHz bus. I suppose you'd want those faster specs especially @ 50 MHz.

But yeah, 15ns should be good enough.

I guess so. I'm running these 15ns at 66MHz FSB. Although timings are fully relaxed. Not sure what is the limit at 66MHz operation.

You'll get around 2-5% extra performance with maxing out the cache.

Going from 128KB to 1MB cache will incrase performance for more than 5%. It depends largely on the app running but should be closer to 10%. As it can be seen here:
Re: Phil's Ultimate VGA Benchmark Database Project

kixs wrote:

I guess so. I'm running these 15ns at 66MHz FSB. Although timings are fully relaxed. Not sure what is the limit at 66MHz operati […]
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I guess so. I'm running these 15ns at 66MHz FSB. Although timings are fully relaxed. Not sure what is the limit at 66MHz operation.

You'll get around 2-5% extra performance with maxing out the cache.

Going from 128KB to 1MB cache will incrase performance for more than 5%. It depends largely on the app running but should be closer to 10%. As it can be seen here:
Re: Phil's Ultimate VGA Benchmark Database Project

Yes, from 128KB, closer to 10% should be realistic in some apps. My benches have been on 256kb vs 1024kb, so that's why I mentioned 2-5%. It will also vary from chipset to chipset and CPU type. I can't find my 486 cache benchmarks at the moment, but here are for Socket 5 and 7. Several boards have been tested with different cache settings: Socket 5 & 7 Motherboard VGA Benchmark comparison

chrisNova777 wrote:

what about price. how much approx does it cost to get a set of 1mb? (8 chips x ??kb?)

Note there are actually nine SRAM sockets; two banks of four and the tag SRAM. You can use a smaller capacity chip for tag, the board requires a 64Kx8 or bigger for 1024KB.