Debugging a RAM upgrade and slow OS X performance

Aug 06, '01 09:46:03PM

Contributed by: aalegado

[Editor's note: Here's a story of a user experience with a RAM upgrade that was anything but normal. If you upgrade your RAM at some point in the future and are faced with extremely slow system performance, you may want to remember this article's suggested fix...]

I recently installed additional RAM in my G4 450DP running OS X v10.0.4. I went from 640MB (128MB + 2x 256MB DIMMS) to 1128MB by adding a single 512MB DIMM. The installation was NOT routine.

The system ran normally before installation. After installing the DIMM, all system operations were noticeably slow. The boot process took longer than normal and even the insertion point in the login window blinked at a dramatically slower rate than normal. I could type my username and password blind and not see the character echo for close to 2 minutes.

Once logged in, all my login apps would attempt to start and then quit prompting the standard system message. It would take about 3-5 minutes between each app to get the quit-message. At no time was I able to do anything useful in any application. The system was just too slow. The pointer did move as fast as normal...the system was just unresponsive to clicks or drags.

Read the rest of this article for more detail on the troubleshooting Alex did, and his eventual solution...along with a question about why this happened.

I began to try to solve the problem by removing the just-added DIMM. Next I tried the new DIMM by itself. Next I tried just the original 128MB DIMM. I tried several different variations of new DIMM only, old DIMMs only, old + new DIMMs, and various slot assignments. All attempts ended in the same behavior--slow boot-up, slow login, slow application loading, unusable system.

OK, try some more serious things: I zapped PRAM the normal way (CMD-CTL-P-R) without noticeable affect. Finally, I got out the tactical nuke: I pulled the chassis from my shelving unit and set it out on a work platform. I pulled the motherboard battery and pressed the internal reset button. I left the battery out 30 minutes and worked on my iBook.

At one point in this exercise I looked at my iBook and thought, "Looks like this is my only working computer" and I was wondering if Apple would honor a AppleCare renewal I'd just mailed the previous day. :(

But...that fixed it. The system came up normally as if nothing had happened.

I don't understand the relationship between OpenFirmware and the kind of hardware change I made but clearly I had to do a drastic thing to my system to work properly.

Can anyone clue me in as to why I had to do what I did? How about other things I might have tried?

Thanks.

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