The Power Mac 4400 RAM thread

XodiumRetro

Tinkerer
Oct 25, 2021
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Central Coast, California
xodium.net
This was previously a question thread, however upon experimenting myself I wanted to update with my findings.

First, the big one:

Does refresh rate matter? Yes, yes it does, but not from a "will it even work" perspective. Refresh rates below 2K are fully addressable by the 4400, but 4K? The 4400 can only address half the RAM module for 4K refresh modules. So if you have a 64MB module with a 4K refresh rate, the 4400 will only see 32MB of it. Kind of a waste to be sure, but if you need RAM in a pinch it IS quite nice to be able to just grab whatever EDO you can find and know it'll at least "work" to some extent.

So ideally, you want to find 2K refresh modules so you don't end up wasting half the module, but if you can't...

Next, unbuffered vs. buffered: 168-pin EDO have two notches cut in the RAM module. The outermost notch determines if the module is buffered or unbuffered.

Is the notch symmetrical between the two sets of pins? If so, that's a buffered module. May work in other machines, but won't work in the 4400.

Is the notch offset toward the inner set of pins? If so, that's an unbuffered module and will work fine in the 4400 (and other Macs that need unbuffered.)

Also, be wary of RAM voltages. The 4400 needs 3.3v modules. Some other Power Macs (like the 6500) want 5v. Very easy mistake to make when looking for RAM.

Lastly, where to get this stuff: As of this writing I bought my RAM from a shop called Memory Masters on eBay, it was roughly $19 USD after tax for a 64GB 4K refresh module. And I can report that short of losing half the rated capacity of the module due to the refresh, the module works perfectly and is also single banked, so it can be run in the first slot of the 4400 with no issues whatsoever. Nice.

So, in the end, the big question was "does 4K refresh matter"? and the answer is, well...kind of. You can buy RAM without worrying about it, just don't expect the full RAM module to be addressable by the 4400. Other Macs with EDO apparently don't have this issue, however.
 

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JustG

New Tinkerer
Dec 12, 2021
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Anyone have a source for correct memory for the Tanzania based computers? Looking to max out mine. I sent a message to xodium but he doesn't seem active any longer.