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20th Anniversar Mac (TAM) Memory Upgrade

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Shadow Lord

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Hi,

Can anyone tell me what memory sticks work to max out a TAM? I was told that 64MB Un-Buffered EDO 5V RAM would work. However, Wikipedia states that the system uses 3.3V EDO OR FPM memory. So which is it? 3.3V or 5V? And between EDO vs. FPM is one faster/better? Thanks.
 
The TAM is essentially a Power Macintosh 6500 internally. 5V EDO is my recommendation for these machines. 64MB is the largest size supported. Apple says FPM won't work, though I've heard of other people using it, but these machines have EDO support in the memory controller and will benefit from the increased performance. My TAMs both have EDO.

The only Power Macs which use 3.3V are Tanzania systems, such as the 4400 and the StarMax 3000 and 4000 series. The good news is the wrong RAM won't even fit.
 
HoJoPo said:
This page seems to be put together by a TAM owner, so may have the best information: https://web.archive.org/web/2003081...ingmind.com/twentieth/twentieth_upgrades.html

EDO would be faster, but sounds like there are some very specific issues as to the compatible RAM type.
Click to expand...

Thanks for the linkage. Great this one now says 5V. So two votes for each! :) Also how would one know (aside from checking datasheets) 1K/2K refresh? Can it be determined from part number directly? Thanks.
 
ClassicHasClass said:
The TAM is essentially a Power Macintosh 6500 internally. 5V EDO is my recommendation for these machines. 64MB is the largest size supported. Apple says FPM won't work, though I've heard of other people using it, but these machines have EDO support in the memory controller and will benefit from the increased performance. My TAMs both have EDO.
Click to expand...

Thanks for the info. BTW: Did you run into the refresh problem referenced on the page linked earlier in the thread?
 
I don't remember the refresh rate on the RAM in my systems, but for the 6500 and TAM, 2K is preferred (though I believe 1K will still work). There have been problems reported with 4K refresh, so avoid those. You'd need to check part numbers on the RAM stick to determine what you're actually using.
 
ClassicHasClass said:
I don't remember the refresh rate on the RAM in my systems, but for the 6500 and TAM, 2K is preferred (though I believe 1K will still work). There have been problems reported with 4K refresh, so avoid those. You'd need to check part numbers on the RAM stick to determine what you're actually using.
Click to expand...

Thanks for the help. I will keep an eye out and see what I can find. While on the topic of RAM anything special I should watch out for on the Apple 9600? Or will plain old 128MB 168pin SDRAM do it? TIA!

EDIT: To answer my own question it isn't SDRAM but 168pin EDO 5V w/ 2K Refresh
 
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ClassicHasClass said:
The good news is the wrong RAM won't even fit.
Click to expand...

But it still won't stop stupid. The only mechanical difference between a normal 3.3v SDRAM DIMM and a 5v EDO DIMM is one of the keyed notches is moved over slightly.

I remember back in the day reading usenet posts where people took dremels to either cut the key out of the DIMM slot on the motherboard or widen the key on the DIMM itself so 3.3v DIMMs would fit in the 5v EDO Powermacs.

Of course doing this usually caused either the DIMM or motherboard to let out the magic blue smoke. I recall a handful of users reporting it actually worked but it was likely BS.
 
I did that on a lark once, I had a pile of unused ram and a 8500 that needed more, it did indeed release the magic smoke from the ram
 
So finding RAM is proving harder then I thought. I can find the rightish RAM but determining if it is 2K is the problem. Anyone have a reliable CHEAP source they can recommend? Thanks.
 
Shadow Lord said:
So finding RAM is proving harder then I thought. I can find the rightish RAM but determining if it is 2K is the problem. Anyone have a reliable CHEAP source they can recommend? Thanks.
Click to expand...

Try contacting Other World Computing: https://www.macsales.com/

They used to carry a lot of legacy Mac hardware and might have the RAM for your TAM.

About 5 years or so ago, I bought 128M of RAM for my SE/30 from them.
 
HoJoPo said:
Try contacting Other World Computing: https://www.macsales.com/

They used to carry a lot of legacy Mac hardware and might have the RAM for your TAM.

About 5 years or so ago, I bought 128M of RAM for my SE/30 from them.
Click to expand...

Thanks. They are a bit on the expensive side ($19.98/ stick for the Power Mac 9600 memory). They also list the memory as 4K refresh which I don't believe will work with the 9600.

No memory for the TAM according to the CSR on Live Chat.
 
4K refresh works fine with the 9600. It just doesn't work with the TAM.

You're not going to find it a lot cheaper, I'm afraid. I usually buy from MemoryX but they'll be about the same, if not a bit more.
 
ClassicHasClass said:
4K refresh works fine with the 9600. It just doesn't work with the TAM.

You're not going to find it a lot cheaper, I'm afraid. I usually buy from MemoryX but they'll be about the same, if not a bit more.
Click to expand...

Well, if 4K refresh works (I am trying to find the source which said 2K although now I am finding sources that say both) then memory should be easy to find unless I am missing something else?

Edit: I know in the 9600 EDO vs. FPM is pointless but how about buffered vs. unbuffered? Does the 9600 have to have buffered memory? How about the TAM?

Sorry for all the questions but I am not very familiar with Macs and generally in the PC world as long as I am buying the right type of memory you are good to go :).
 
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Buffered is preferred for both, but unbuffered should work at least in the 9600 (but avoid mixing them - it may work fine but others have reported odd issues). I don't know if unbuffered will work in the TAM, though I don't see why not. That said, just get buffered RAM and don't worry about it.
 
Shadow Lord said:
Edit: I know in the 9600 EDO vs. FPM is pointless but how about buffered vs. unbuffered?
Click to expand...

Buffered memory is a memory module which has a set of registers on it (usually a single discrete chip in the middle of the module) which data is queued in before being sent to/from the memory controller.

It has the disadvantage of being slower than more common unbuffered memory because of extra wait state penalties from the registers, but has an advantage of putting less of an electrical load on the memory controller and improving system stability when ridiculous number of memory modules are used (like 12 on the PM9600.)

Unbuffered memory should work fine on the TAM if it's similar to a PM6500 internally. I have a Performa 6500/250 which is essentially the same and unbuffered memory works fine in it.
 
Shadow Lord said:
So finding RAM is proving harder then I thought. I can find the rightish RAM but determining if it is 2K is the problem. Anyone have a reliable CHEAP source they can recommend? Thanks.
Click to expand...

I think the vast majority of 4Mx4 chips are 2K refresh (aka 11 by 11 addressing).
 
GiGaBiTe said:
Buffered memory is a memory module which has a set of registers on it (usually a single discrete chip in the middle of the module) which data is queued in before being sent to/from the memory controller.

It has the disadvantage of being slower than more common unbuffered memory because of extra wait state penalties from the registers, but has an advantage of putting less of an electrical load on the memory controller and improving system stability when ridiculous number of memory modules are used (like 12 on the PM9600.)

Unbuffered memory should work fine on the TAM if it's similar to a PM6500 internally. I have a Performa 6500/250 which is essentially the same and unbuffered memory works fine in it.
Click to expand...

I think buffered and unbuffered uses different notches, and Power Macs (including the 6400/6500) mostly use 5v buffered with some exceptions. I think the DIMMs that will work in the 6400/6500 will have 32 or 36 4Mx4 chips (16Mbit).
 
Notch position is true for 168 pin DIMMs:

dimmkey1.gif


The smaller key decides whether the module is buffered or not and the middle notch decides the voltage.

But for DDR-DDR4, the notch is standard regardless if the module is buffered or not.
 
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