Date: Mon, 6 Oct 2003 19:21:49 +0100 Subject: Re: ram for LC III From: Mark Benson <[EMAIL PROTECTED]>
on 10/6/03 4:57 AM, williamd at [EMAIL PROTECTED] wrote:
I recently installed a 32mb EDO simm in my LC III. So far I see no ill effects, but am wondering whether this is indeed ok?
I don't have any problems with using EDO in LCs. I can't tell the difference and so have no doubt got it in some somewhere. I have a 64MB in my Quadra 805 hack (LC475 board) and also in my Performa 475 and they don't work in anything else other than a 63x series. Basically unless you get outside it's supposed RAM limits I don't think it matters.
There's an old Apple Tech Note on memory which states, among other things, that EDO is perfectly OK in their machines, except the 7200, and I'm not sure that the 7200 existed when this tech note was written, so it may just say it's OK.
Ah, here it is. Tech Note TN1055, "SIMMs to DIMMs: Making Sense out of Memory Expansion for the Power Macintosh."
"What is EDO memory and do Macintosh computers support it?"
"EDO (Extended Data Out -- sometimes called hyperpage) memory are DRAM devices that improve access timing by extending its data out timing while allowing the memory controller to address the next column address. Although EDO devices will improve timing efficiency to main memory by approximately 10%, it does not necessarily mean programs will execute 10% faster; much of the time the CPU fetches instructions and data from cached memory, i.e., L1 cache within the PowerPC microprocessor and or L2 cache on the mother board.
"EDO DRAM is a superset of conventional (also called Fast Page Mode) DRAM. This means that an EDO DRAM can be used in place of a Fast Page Mode DRAM, although unless the memory controller is designed to utilize the faster EDO timing, the memory performance will be the same as Fast Page Mode.
"Power Macintosh computers do not yet support the extended data out timing that EDO DRAM devices can provide. If memory modules with EDO DRAM are designed to be fully compatible with standard Fast Page Mode DRAM, however, they should function properly. (Be sure to check with the SIMM or DIMM manufacturer and specify the Macintosh model.)
"In the future, PowerMacs will support the extended data out timing, taking full advantage of EDO DRAM devices."
I guess it doesn't actually mention machines earlier than the Power Mac. We can hope that if any earlier machines had an issue that they'd mention it.
Oh, in other news, in Tech Note HW515, "Memory Hardware Q & As" it states:
"My Macintosh IIsi reboots whenever it's shut down, like the power switch is in the locked position. What could be causing this?"
"A DTS engineer here ran into this very same problem with his Macintosh II, and was able to rectify the problem by zapping the Parameter RAM (PRAM). He'd tried reinstalling the system files as well as a new keyboard, but that didn't solve the problem. In order to zap the PRAM, hold down Command-Shift-P-R while starting up your machine.
"If zapping the PRAM doesn't do the trick, you might consider taking your machine to a local service provider (Apple authorized, of course) to see if there is a hardware problem/failure with the power switch in the back of the CPU. For more information on service providers, please contact the Apple Assistance Center at (800) 776-2333."
For the person whose IIcx won't shut down. You may have already tried this, but I figured it couldn't hurt to quote it.
Jeff Walther
-- Vintage Macs is sponsored by <http://lowendmac.com/> and...
Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! |
Support Low End Mac <http://lowendmac.com/lists/support.html>
Vintage Macs list info: <http://lowendmac.com/lists/vintagemacs.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/vintage.macs%40mail.maclaunch.com/>
Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
