At 15:30 -0400 08/31/2004, PCI PowerMacs wrote:
From: Bruce Johnson <[EMAIL PROTECTED]> Date: Mon, 30 Aug 2004 14:47:32 -0700
snipThis is largely an accident of Apple's timing. Apple jumped on the DIMM bandwagon early, and settled on the 5V first generation DIMMS.
Apple never made any systems (afaik) with the 3.3V EDO DIMMS, bit went right to the PC66 SDRAM in the Beige G3's.
I think that the 4400 used the 3.3V DIMMs but I'm not certain about that. There was one oddball economy model that did, IIRC.
From: <[EMAIL PROTECTED]> Date: Mon, 30 Aug 2004 23:13:58 -0400
That is EXACTLY what I mean. Think about the typcal 168-pin DIMMs that you have seen used in PCI Macs. The word for them is "chunky."
I purchased some 168-pin DIMMs that look just like the usual 5v FPM 168-pin DIMMs but they probably weigh about half as much. All of the chips on both sides of the DIMM are very, very thin. I'm away from home right now so I can't pop one out of the 9600 to check but I'm sure that they say 3.3v right on them, run at 60ns, and are designated IDT 74FCT 162244 APA.
They work just fine in a 5v Macintosh environment.
I think that you will find that there are voltage regulators (little three pin component, looks like a minature TO-220 package) on those DIMMs to reduce the supply voltage from 5V to 3.3V. Giving a chip which is rated for a 3.3V supply voltage a 5V source is a *Bad Thing* tm.
As such, they will work in a 5V environment, but almost certainly not in a machine that requires 3.3V--although they might. It depends on the voltage regulator used.
Jeff Walther
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