LC 575 Memory Limit

[luddite]

According to most docs the LC575 maximum RAM is 36MB, though I've found a few mentions of 68MB being possible... I wonder if anyone's done this (or more?) and how it turned out. Any stability issues?

 

[LCGuy]

The LC575 is basically a 475 with a faster CPU and a built in display. I've heard of people taking LC475s all the way up to 132MB before, so I can't see why you wouldn't be able to do it with the 575.

 

[Charlieman]

Chris Lawson's research is reported at:

http://macfaq.org/hardware/memory.shtml

Locating a suitable SIMM today may be more difficult, so be prepared to buy a few and make sure that you have a generic PC or whatever in which to install the majority that don't work. SIMMs identified as working in a PowerMac 6100 or Acorn RISC are a decent bet.

 

[tmtomh]

I've had at least two LC575 boards that ran fine with 128MB SIMMs installed. True, they need to be the right kind (single-banked - which has nothing to do with whether the SIMM is one or two sided or not) - but with the right kind, the machine runs great.

 

[Franklinstein]

Just bought a new keyboard for my peecee, so I figured I'd break it in a bit. I LUUUURVE scissor keys.

AFAIK, the Mac TV was the only Mac where the Apple-specified limit was actually adhered to; virtually every other machine could accept waaaay more than Apple claimed. I've got a small cache of 64 and 128MB 72-pin SIMMs, and in all the machines I've tried them, from LC IIIs to 8100s, they've all been recognized fully. A 6100 with 264MB of RAM (128x2 + 8MB soldered)is a trip. So is a Quadra 840AV with 512MB (128x4).

The PowerBook 2400c is quoted by Apple as having a max of 80MB (64MB SODIMM + 16MB soldered), though a Japanese company made a 96MB SODIMM that brought its max beyond that limit to 112MB.

Really, the limits are set when engineers test the maximum of readily available RAM modules, and you know how technology can progress.

Then, of course, there's the Mac TV. It completely refuses to use more than 8MB of RAM. Something about the weird circuitry they used to accommodate the TV system, I dunno. But it sucks, and a stripped System 7.5.5 with ClarisWorks 4.0, maybe with Oregon Trail or SimCity 2000 for games, is all I care to run on that thing.

 

[luddite]

Chris Lawson's research is reported at:http://macfaq.org/hardware/memory.shtml

Locating a suitable SIMM today may be more difficult, so be prepared to buy a few and make sure that you have a generic PC or whatever in which to install the majority that don't work. SIMMs identified as working in a PowerMac 6100 or Acorn RISC are a decent bet.

I've found 64MB SIMMs at Memory Ten, but so far nothing bigger. Something tells me that 68MB in a 575 might actually be plenty ;-)

 

[phreakindee]

My LC575 has 68MB installed with 7.5.1 and stock components, I have never run into any stability issues at all - also then upgraded the CPU to a full '030 33Mhz, still runs great even at longer stretches.

 

[register]

A nice possibility you have with plenty of RAM is to use a RAM disk to contain system and application software and to run the beast with virtual memory off, or to use a RAM disk as a scratch disk (for number crunching, graphics manipulation or a software RIP). Top performance!

Btw: please be so kind and share your experience with the rest of us, improving the 68kMLA Wiki -> RAM module test results. This might save some money one needs not spend for known not working combinations.

 

[Outlander]

According to most docs the LC575 maximum RAM is 36MB, though I've found a few mentions of 68MB being possible... I wonder if anyone's done this (or more?) and how it turned out. Any stability issues?

At the time the LC575 was released the maximum memory size per SIMM was at 32MB's Today you can purchase SIMM's of 128mb's

 

[register]

I read about Mystic CCs (= LC 575) pushed to the limit with use of a 128 MB memory module. I verified the nice operation of such module in a LC 475, no issues besides the extraordinary long duration for the memory count step in the boot process. In case you want to purchase a 128 MB PS/2 RAM module, be aware of the fact that not only different elctrical specified modules are available, but also different physical dimensions. Some modules will not fit into most machines without changing the angle of the slot or cutting out in the case. A module specified for a Performa 630 might be electrical compatible to a LC 475, but might interfere with the CPU chip or a heatsink.

 

[mcdojf]

Just posted this on the Trading Post forum, but thought I'd include it here, too:

I found a pretty good deal on eBay for 128MB SIMMs that I have confirmed are compatible (and small enough to fit properly) in the LC 475 / Quadra 605.

Samsung 128MB 32x36-60ns ECC SIMM KMM53632000AK-6U

$13.50 each with free shipping

http://cgi.ebay.com/Samsung-128MB-32x36-60ns-ECC-SIMM-KMM53632000AK-6U_W0QQitemZ110331791958QQ

My guess is these would also work fine with the LC 575

The auction indicates the seller has more than 10 available.

 

[System6+Vista]

Just posted this on the Trading Post forum, but thought I'd include it here, too:
I found a pretty good deal on eBay for 128MB SIMMs that I have confirmed are compatible (and small enough to fit properly) in the LC 475 / Quadra 605.

Samsung 128MB 32x36-60ns ECC SIMM KMM53632000AK-6U

$13.50 each with free shipping

http://cgi.ebay.com/Samsung-128MB-32x36-60ns-ECC-SIMM-KMM53632000AK-6U_W0QQitemZ110331791958QQ

My guess is these would also work fine with the LC 575

The auction indicates the seller has more than 10 available.

Um, I'm really looking for a 128mb module for my Mystic CC so I was about to jump on this but then I realized that this is 60ns. Many sites (including low end mac: http://www.lowendmac.com/500/performa-575.html) list the machine as using 80ns RAM. Is the 80ns a minimum or maximum? How much would you expect speed to deteriorate using 60ns?

 

[LCGuy]

60ns RAM is faster than 80ns RAM, so I can't imagine there being a problem, it would likely just go back to 80ns, in the same way as if you use PC133 in a PC100 system (like a G3/G4), it just clocks back to the slower speed.

 

[register]

Samsung 128MB 32x36-60ns ECC SIMM KMM53632000AK-6U

This module seems to be of "parity" type. Could someone please confirm it does work and fit properly inside a LC 475? Uptil now I was not lucky with parity EDOs in my LCs. Also this module is not what I would call a low profile module. It might interfere with the case of a CC (even with proper clearance inside the case a problem might occur when you try to slide in the mainboard.

 

[Bunsen]

A 6100 with 264MB of RAM / is a trip. So is a Quadra 840AV with 512MB

The 6100 shipped with a 256MB hard drive 8-o

It would no doubt make video capture a breeze, if you

use a RAM disk

 

[mcdojf]

Samsung 128MB 32x36-60ns ECC SIMM KMM53632000AK-6U

This module seems to be of "parity" type. Could someone please confirm it does work and fit properly inside a LC 475? Uptil now I was not lucky with parity EDOs in my LCs. Also this module is not what I would call a low profile module. It might interfere with the case of a CC (even with proper clearance inside the case a problem might occur when you try to slide in the mainboard.

This module does fit properly and works perfectly inside a LC 475 (see the rest of my previous post here). I can't speak to the possible clearance issues in the Color Classic, however.

 

[luddite]

I was pretty excited until I saw the $27 international shipping fee

 

[register]

This module does fit properly and works perfectly inside a LC 475 (see the rest of my previous post here). I can't speak to the possible clearance issues in the Color Classic, however.

Very nice: "strong buy!"

 

[System6+Vista]

The 128mb stick referenced above works correctly and fits in my Color Classic on the LC575 motherboard with 33mhz 68LC040!