View Full Version : Installing Memory

02-01-2001, 12:07 PM
I have a Power Macintosh G3 Beige which uses the low profile memory cards, with two 64MB chips installed, can I install a 128 MB chip in the other slot along with the 64MB chips already installed
I would appreciate any information you could give me


02-01-2001, 01:29 PM

02-01-2001, 01:31 PM
sure you can. I would add a PC-100 128Mb SDram chip. Works well in the Beige G3 machines.


Big Al
02-01-2001, 03:22 PM
You might check with others, but when I install new memory I always put the largest DIMM in the first bank and then next largest, etc. This is not for older Power Macs where you can match the pairs for interleaving.

02-02-2001, 12:21 AM
Big Al, I've never heard of this before. I'm just curious where you heard to do this? For what machines is this a good idea to do (if it is)?

02-02-2001, 04:42 AM
Hi guys....

Actually, there is a recent discussion on this forum about density/install order and the effect it has on the memory controller's memory access/possible latency.

All I remember is what is relative to Tsunami Arch. memory. For interleaved RAM, like in my PTP largest stick pairs in A4 & B4, next largest in A3 & B3, and so on.

Guru's can elaborate, but I believe that TECHNICALLY, this is true of all PCI macs. In practice it's likely a YMMV issue. Which ever slots the memory controller looks at first is where the RAM sticks should go first. On Tsunami based PTP's it's A4, B4.

You learn something new every day around here, eh?

Hey, I'm the proud owner of another PTP!!! I have one running my biz stuff, and another one for souping up. Woo hoo!!!

A trip to Australia may delay my hot roddin the extra one. A problem I can live with.



[This message has been edited by crazyeights (edited 02 February 2001).]

[This message has been edited by crazyeights (edited 02 February 2001).]

Big Al
02-02-2001, 11:57 AM
Don't remember where I read it, but the idea is that if you are using less than the installed memory (non-interleaved) you won't have to address all the sticks if the first one is large enough. The longer you leave your machine on and the more programs you open the less benefit from this technique because once you use all the memory it's probable that the active memory is spread across all the sticks. Seemed to make sense to me and I didn't see how it could hurt so that's what I do.

02-02-2001, 02:00 PM
This is all certainly the case for legacy Macs, however, I have never seen anything written concerning the order for the non-interleaving G3's and G4's. Surely the newer machines look for RAM in a certain sequence but I don't know the sequence. It may be of insignificant importance since everything is so much faster in the newer machines.

The beige G3, for instance, has three RAM slots, J5, J6 anf J7. I start with the larger pieces in J7 simply because it's closer to the processor. I have no idea if this is right or not.

02-02-2001, 02:58 PM
I've never seen any technical discussion of this aspect of memory installs on later G3's and G4's. All the tech docs say is that the memory controller treats all memory as one contiguous memory space, and does not support interleaving. There is not, the Developer's note continues to state, any benefit derived from installing any piece in any particular order.