Replacement Memory for Compact Mac?

[Hurry]

I asked on Discord but this might be better as a thread for posterity in case someone else has the same questions.

I have an SE/30 and a Classic II (the 4MB onboard version). I'd like to upgrade the memory in the SE/30 and replace the memory in the Classic II as I believe it may be faulty. I'm having a devil of a time interpreting documentation to determine what I want to buy. eBay seems to be the only source and I don't trust sellers to know what they're selling.

According to multiple documentation sources, mainly Technical Bulletin #176 (compiled helpfully here at the Table of Macintosh RAM Compatibility) the SE/30 requires 30-pin SIMMs that have a minimum refresh of 120ns. The Classic II requires minimum refresh of 100ns.

However, my Classic II came with a pair of Motorola ATATCD9222 80ns SIMMs, and the SE/30 is loaded with Samsung KMM581000BP-8 SIMMs. The Samsung reference I found online described these as 80ns as well.

Finally - I search eBay and find a listing for Macintosh Classic II memory, but these SIMMs are described as being only 60ns!

Questions:

1. Am I reading this wrong? Misunderstanding the documentation?
2. Is the documentation CYA by Apple and for practical purposes lower refresh speeds are just fine?
3. Do you have any recommendations for where to pick up memory / good experiences with any specific eBay resellers you can pass on?

Bonus Question:

I know the Classic II is capped at 10MB, and the SE/30 has a very high ceiling with proper software/mods. I am not looking to Tim Allen the SE/30, I just want comfortable headspace so i don't have to think about memory. What's the sweet spot? 16MB?

 

[eric]

2. Is the documentation CYA by Apple and for practical purposes lower refresh speeds are just fine?

Lower is fine, lower means it can refresh faster, but doesnt have to. Higher means it'd take longer to refresh and wouldnt work.

What's the sweet spot?

I have 65mb in my SE/30 - it was cheap and the startup RAM check isn't forever. But really I think it's too much. I doubt there are many '030 apps that would benefit from that much RAM. One thing you can do with that much RAM is have a RAM disk, which can be nice for some apps.

As to where to buy them, looks like the sellers I got from before are no longer listed on amazon. I'd guess due to recent popularity dwindled their stock.

 

[Hurry]

Thank you! I received the same advice on Discord from ScutBoy.

Being new to this platform, I think I was over-concerning myself with the thresholds of how much faster they can go.

 

[Kai Robinson]

@Zane Kaminski will sell you compatible ram, from Garrett's Workshop.

Also, I've had 1mb module PCB's from github, that I assembled, that worked just fine.

 

[rikerjoe]

For what it is worth, I've used modules from Memory Masters on eBay for several SE/30s, a Color Classic, a Mystic upgraded Color Classic, and a Centris 650. All have worked just fine and I have no complaints.

 

[Hurry]

For what it is worth, I've used modules from Memory Masters on eBay for several SE/30s, a Color Classic, a Mystic upgraded Color Classic, and a Centris 650. All have worked just fine and I have no complaints.

Right on - that's exactly who I ended up making my purchase from. I reached out last week to ask the same question and had a great back and forth with them. They couldn't answer my question and didn't have what they felt would certainly work in stock at the time (but do now). The person I chatted with even asked me if I'd take photos of the inside of my Classic II for them while I had it open. Kind of a cool sign that they're trying to have an inventory of that sort of thing. Seems less cynical and more customer service oriented than a lot of places.