7100 L2 Cache SIMM

[Markintosh]

Hey gang,

I need help understanding what the L2 Cache chip actually is. It clearly uses the same form factor as the ROM, but how do I identify one for purchase? I'm not even sure the maximum size allowable either. I've seen 256K and 4MB. I also don't know how to distinguish one from a ROM SIMM.

Any help would be appreciated.

Thank you,

Mark

 

[Fizzbinn]

I have a resource article on Power Macintosh L2 Cache DIMMs that includes info on identifying those compatible with 61xx/71xx/81xx models:

https://tinkerdifferent.com/resources/ppc-macintosh-l2-cache-modules.19/

Unfortunately it seems these are not exactly easy to find on sites like eBay. I think once they get separated from their machines they often end up mixed in with RAM or confused with ROM modules....

 

[Markintosh]

Thank you-that is a GREAT reference link. Ok, so finding one on eBay may take time. Does anyone make recreated versions of these?

 

[JustG]

I remember there being a thread over on the MLA talking about recreating them, I don't think it ever got anywhere past the discussion phase though. Too bad, I would be interested in several for my x100 machines.

 

[Markintosh]

That is too bad. I think a lot of people would be interested...

 

[Kai Robinson]

A few of us once talked of such a thing... Perhaps @Zane Kaminski might jump on board with a fresh design - I know a 1mb L2 would sell like hot cakes

 

[Markintosh]

I think so too-I'd buy one

 

[Fizzbinn]

Here‘s one:

Micro Systems 256KB Cache DIMM Memory SMA256CA/6 Apple Power Macintosh PowerMac | eBay

<p dir="ltr" style="margin-top:0; margin-bottom:0; text-align:start;">Micro Systems 256KB Cache DIMM Memory SMA256CA/6 Apple Power Macintosh PowerMac zu verkaufen.</p> <br> <p dir="ltr" style="margin-top:0; margin-bottom:0;">Ungetestet. Zustand und Lieferumfang siehe Fotos.</p> <br> <p dir="ltr"...

www.ebay.com

 

[Markintosh]

Shoot-I missed it-SOLD already! Thanks for the post!

 

[trag]

The crazy thing is that MacSales (OWC) had hundreds of the 256K modules and was selling them for about $.25 each if you bought a hundred or so.

All gone now. I don't know what they did with them. Probably scrapped. I kept thinking about buying a lot, but couldn't think of any use for SRAM chips of such small capacity. They had the type shown in the A03 reference above, I think. 256MB divided amongst 8 chips is not much capacity per chip.

I believe one of the primary obstacles to recreating caches is the difficulty of sources TAG RAM.