Power Macintosh and Memory

[Techwhore]

I've got an old Power Macintosh 7500/100... i know it's mad old school but it was free. I read on the apple specs page that it takes 168 pin DIMMs and was wondering if i need proprietary apple memory or if i can use the 128 megs i have laying around (pc100 cas3)?

I'm also thinking about poping in one of those G3 or G4 upgrades, but they're expensive and i don't really have a use for this box yet, so... we'll see.

It's got 72 mb ram now, and 8 DIMM slots. Would i be wasting my time trying to put the memory i have in?

Thanks

 

[GonzoDaGr8]

As far as i know, not until they got into the G3's and G4's, did Apple use standard memory. Example, PC100, PC133. I would figure it to still need the Apple proprietary stuff. Hope that helps. Would i be wasting my time trying to put the memory i have in? Shouldn't hurt to try..The most that would happen is no-post. I tried using PC compatible 72 pin SIMMs' in a performa and just got no post. No harm done though.

 

[pukemon]

Old Power Macs used 5V FPM DIMMs with some peculiar timings... Standard PC100/133 are as far as I know, 3.3V. So it really won't work, but you could try...

 

[NOE]

What would happen with the RAM then? I mean, if the Mac uses 5V and the RAM 3.3V? Would it still just not POST or would it burn the RAM?

 

[Techwhore]

I doubt it'd burn the ram, but i could be wrong... I wouldn't be losing much if it did, i mean pc100 cas3 is dirt cheap... probably cost more to have it shipped than the product itself.

 

[kgraeme]

I don't know what PC100 ram would do, but I know that it likely won't work. The memory these old macs used was standard in its day, but PC100 was its successor. I recall that some old PCs used the same 168pin DIMMS.

You can buy the ram from vendors like Crucial or Viking. I did a quick search at Crucial and found this. Note that it's for the 7600 model, not the 7500. For some reason, Crucial's database only came up with a 32MB match for the 7500, but offered a 64MB for the 7600. If memory serves, the logic boards are effectively identical and they can use the same ram. You'll also notice that the price for 64MB is $52.19. That's because supply/demand never brought the price of these modules down.

BTW, I know how it feels to have an old clunker that you want to get running. I have one of the last model, pre-PowerPC chip Macs. I couldn't even get rid of it with a monitor and software bundle at a garage sale.