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Mac isii RAM issue
Posted by: Schmooves1 on 2024-06-17 02:35:20
I have a Mac isii with 4 1Mb SIMMs, but it's struggling to run applications that require 2000K RAM. Anyone know why "system software" is eating so much of it? Just bad chips? I've tried cleaning and reseating the SIMMs but I'm honestly thinking of just buying some new ones to see if they'll work. Figured I'd see if anyone else has some input before spending the money on only a potential fix.
Posted by: cheesestraws on 2024-06-17 02:47:54
This is almost certainly a software issue not a hardware issue.

What does the system's memory footprint look like if you boot with extensions off? (Hold the shift key while booting)
Posted by: mg.man on 2024-06-17 03:57:10
Anyone know why "system software" is eating so much of it?
Have you checked that 32bit Addressing is turned on? Open the Memory Control Panel to check / set.
Posted by: mikes-macs on 2024-06-17 04:00:50
After confirming that 32 bit addressing is turn on, perhaps use virtual memory or buy bigger simms. I have 4 each 2 mb simms if you want them.
Posted by: cheesestraws on 2024-06-17 04:04:34
Have you checked that 32bit Addressing is turned on? Open the Memory Control Panel to check / set.

No need for 32 bit addressing for 4 meg of RAM - only if you want more than 8 IIRC?
Posted by: MacKilRoy on 2024-06-17 12:36:30
Possible reasons:
Disk Cache size too big. 32 bit addressing not set. Too many system extensions installed.
Posted by: mikes-macs on 2024-06-17 12:46:40
No need for 32 bit addressing for 4 meg of RAM - only if you want more than 8 IIRC?
True, but in 24 bit mode the operating system takes most of the unallocated RAM usually leaving hardly anything available for applications.
Based on the photo posted it shows that there is available RAM so I assume that 32 bit is already on.
Posted by: cheesestraws on 2024-06-17 16:19:56
True, but in 24 bit mode the operating system takes most of the unallocated RAM usually leaving hardly anything available for applications.

This is only the case if you have more RAM installed than the 24-bit addressing threshold. Under those circumstances, the extra RAM is shown as allocated to the OS (although note that it isn't actually allocated to the OS in any meaningful way). Under the threshold, 32 bit addressing has minimal to no effect.
Posted by: mikes-macs on 2024-06-17 16:54:20
Oh I see what you mean. That makes complete sense now.
Posted by: Schmooves1 on 2024-06-18 09:47:18
It was an extensions issue, thanks all for all the input. I bought the computer from a university surplus so there were all kinds of now unnecessary networking/file management extensions that I really didn't think would eat up as much ram as they did.
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