Non-parity vs. True-parity RAM

Posted on 1998-05-20
Medium Priority
Last Modified: 2013-11-17
What is the difference between non-parity RAM and true-parity RAM?

I have 80Mb in my PowerMac and need to add another 64Mb.  Previously, I added a single 64Mb 60ns DIMM next to a previously-installed pair of 8Mb DIMMS.

Should I put a "true-parity" 64Mb DIMM in the corresponding slot?  Or will it not work?  How can I tell if I'm getting the best performance from my DIMMs if I do not know if the old 64Mb installed is parity or non-parity?
Question by:archken
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Expert Comment

ID: 1535869
Macs ignore the parity part of the chip if it is present. So, it will work with or without parity-RAM. For more information about upgrading RAM, goto:

Author Comment

ID: 1535870
Well this helps me to better understand of RAM.  Perhaps my question should not be so specific.  Thank you for the web link.  I've downloaded GURU, and yes, it has accurate info about my PowerMac.

So it seems I can totally ignore the aspect of Macintosh RAM being non-parity or true-parity.

This leads to the question of "interleaving memory."  What is it?  How can I tell if I'm benefitting from it?

Do I need to be concerned about the type of my existing 64Mb DIMM when I shop for another 64Mb?  Do I need to match speeds (60ns) or composition (the little black pieces on the chip) to get best performance?  How can I test it to be sure?

Accepted Solution

TheHub earned 400 total points
ID: 1535871
RAM is already fast. Chances are that you would not notice the 10 - 30% increase in speed. However, ones ability to notice said increase has no bearing on the existance of an increase.

interleaving: click on the configure button under the Memory menu in GURU. Up pops a diagram of DIMM slots. interleaving is 2 same size cards in corresponding Ax and Bx slots where x is 1, 2, 3...etc.

Most machines that can use interleaving require 60ns chips.

Composition is irrellevant.

Plug it in.

This response was given in good faith and exceeds the one question limit by quite a bit.

good chips and prices:

good luck

Author Comment

ID: 1535872
Thank you for extending your valuable information to answer my complete question.

Of course your response in good faith deserves the reward of the full 200 points.

Expert Comment

ID: 1535873
groovy man

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