http://discuss.info.apple.com/boards/MacOS.nsf/ccb088a1de6aac738525631c0067846b/82289ABC3647D70B86256724001108ED?OpenDocument
Subject: The Last Word...I Hope Author: Jeffrey Jakucyk Posted: Thursday, 2/25/99 9:06 PM CST Email: [EMAIL PROTECTED] Model: System S/W: Mac OS 8.5.1 Category: Mac OS 8.5 (Part II) The Partial Solution: In previous posts of mine, I?ve suggested two different versions of the solution. After testing both ways, I?m finally able to recommend a good way to fix this RAM issue. The following two configurations apply directly to the Power Macintosh: 7300, 7500, 7600, 8500, 8600, 9500 and 9600's. Recently, I've seen this problem appear in computers that don't fall under this list. I've seen posts regarding this problem with just about all 7xxx series Power Macs, 6400's and 6500's and beige G3's, even some clones! The first suggestion is to follow the advice of the Apple Memory Guide 3/98. According to it you should install RAM chips with the largest ones in the LAST pair of interleaved slots. The next smallest pair of chips go in the next to last pair of slots. I have a 7300/200 with 8 RAM slots, two of which had 16 MB chips already installed in slots A4 and B4. I also purchased two 64 MB chips a few months ago to bump up my total RAM amount to 160 MB. The Apple Memory Guide states that ?DRAM DIMMs can be installed individually; however, to provide maximum performance, install the DIMMs in matching pairs and in paired slots (A4 and B4 first,then A3 and B3, etc.).? So, for my computer, I installed one 64 MB chip in slot A4, the other 64 MB chip in slot B4, one 16 MB chip in slot A3 and the other 16 MB chip in slot B3. If you have only one chip of a particular size, try giving that one its own pair of slots. In other words, put it in the ?A? slot, and leave the ?B? slot free. If I had two 64 MB chips, one 32 M B chip and two 16 MB chips, I would put the two 64 MB chips in slots A4 and B4, the 32 MB chip in slot A3 and the two 16 MB chips in slots A2 and B2, leaving slot B3 open. I have not tested the configuration with a non-interleaved chip, but this seems like the most logical solution. The second suggestion comes from a different tech support person at DMS. He told me to use the opposite configuration. In that case, the largest pair chips go in the A1 and B1 slots, the next smallest pair goes in A2 and B2 and so on. For my computer, I installed one 64 MB chip in slot A1, the other 64 MB chip in slot B1, one 16 MB chip in slot A2 and the other 16 MB chip in slot B2. Conclusions: I tried both RAM configurations, and for a while the second one worked better for me. While the suggestion of the Apple Memory Guide does work better than a random configuration, it did crash and burn on me with no warning. I got away with no crashes at all for awhile, suddenly, I started getting frequent program quits and the dreaded Bus Error at startup. After that problem, I switched my RAM configuration to the way the DMS tech support person suggested. My computer worked that way for a long time with no Bus Errors, but frequent Type 1, 2 and 3 errors. After getting fed up with it, I tried the Apple Memory Guide method again, after doing a clean install of OS 8.5 and updating to 8.5.1 then zapping the PRAM (I recommend zapping the PRAM any time you add or move RAM chips). Miraculously, I have had no startup problems at all since then (whew). I recommend trying the Apple Memory Guide method first, if it doesn?t work well, try the second method. If both of them don?t work, call your memory dealer and see what they think. Keep in mind, this doesn?t appear to affect higher quality RAM, and the problem usually only appears in Mac OS 8.5. The March edition of the Apple Memory Guide can be found on Apple's servers. http://swupdates.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English-North_American/Macintosh/Utilities/Apple_Memory_Guide_3-98.pdf It is a 2MB PDF document that requires Adobe Acrobat Reader to view. If you have any questions, problems or you want some information from the Apple Memory Guide without having to download it feel free to drop me an e-mail. Newest Information: After reading some other posts that appear to be related to this issue, I've come across a few other suggestions that help. I'm surprised that I didn't realize this before, but all my problem applications were ones for which I had turned the Preferred Memory allocation way up. For these programs you need to also increase the MINIMUM amount of RAM for the program. In my case, I even made the minimum and the preferred settings the same. I have also tried turning the disk cache down to 1024k, which seems to help somewhat, but I can't tell. Currently, I have the disk cache turned all the way up, and it actually seems to work better. Maybe it's just the default setting that causes problems. I also recommend using the Mac OS' built-in virutal memory. RAM Doubler is less stable, and running without any virtual memory is not as stable either. I know it can eat up your hard drive space, but it keeps the system heap and application memory requirements in check. I recommend using the patch mentioned on MacInTouch (http://www.macintouch.com) on 2/25/99 that patches the System file for a bug in the code that can corrupt the memory heap (ftp://woodrow.ucs.indiana.edu/Public/Users/joe/MacOS85patch.sit.bin). I don't know yet if this has made much of a difference, but it can't hurt. This may not be related to the memory issue, but running ROM Accelerator (http://www.stg.com/employees/sbytnar/projects/rom_accelerator.html), which maps your computer's ROM into RAM to speed it up, seems to help too. At the very least it cushions some of the performance hits you get from running virtual memory. Hopefully all of the previous suggestions will help you stabilize your OS. Let's just hope that Apple fixes this problem with 8.6. Jeffrey Jakucyk [EMAIL PROTECTED] -- StarMax is sponsored by <http://lowendmac.com/> and... / Buy books, CDs, videos, and more from Amazon.com \ / <http://www.amazon.com/exec/obidos/redirect-home/lowendmac> \ Support Low End Mac <http://lowendmac.com/lists/support.html> StarMax list info: <http://lowendmac.com/lists/starmax.html> --> 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/starmax%40mail.maclaunch.com/> iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
