iMac 333 Memory Upgrade Problems

I have an iMac G3 333 system. I bought it from someone who said they had put a 512MB upgrade inside of it. When I booted the system up, it only read 320MB (1x64, 1x256). I opened the system to upgrade the HD from 6GB to 20GB, only to find out that there was a 512MB PC133 chip in there. So I assumed that this system couldn't read anything over 256MB, I installed a 256MB PC133 chip. Now my system reads 192MB. Why is it only recognizing half of the memory??

Also, I installed my Quantum Fireball 20GB hard drive I pulled out of my Powermac G4 AGP Graphics and it wont boot to it. I can boot a CD and install Mac OS X, but when I restart after installation, it looks for a CD.

As far as the HD, you have to partition the drive so there is an 8 gig partition first (slightly less than 8), and the rest second. Install X on the first partition.
There is a limitation in the rom on boot partition size on the older imacs.

The 333 can use 512mb. Maybe you have a bad mem stick?

Both the 512MB and the 256MB are showing up only half of what they are supposed to. I put the 512MB in my ibook G3 and it worked fine. Second, I partitioned the HD, but it's still not booting. Do I need to change the jumper settings? Again, I can hold "c" and install the OS, but when I go to restart, it comes up with the "?" and can't boot the system.

Make sure the drive jumpers are set to CS or master. What version of X are you installing? The 333 can only run Panther without using something like XPostFacto.

The 512mb stick will not work in a 333. It takes 2 256 sticks to get 512. (and the second one, under the cpu, is a special low profile one).
Dont know why it's not reading the 256.

I've upgraded 2 Rev D 333 imacs to 512 without any problems.

Yeah it would appear that some G3 iMac models accept more RAM while others do not. From iMac G3/333 (Rev. D) - code name: Lifesavers:

RAM: 32 MB, expandable to 384 MB using SO-DIMM SDRAM (3.3V, unbuffered, 64-bit, 144-pin, 100 MHz or faster, 10ns) in two DIMM sockets (256 MB on top, 128 MB on bottom), top DIMM socket accepts 2" DIMM, bottom socket takes 1.5" DIMM
* The exact amount a Rev. A-D iMac can be upgraded varies from unit to unit. We have field reports of some models accepting 256 MB modules in both memory socket and reaching 512 MB - and other reports of early iMacs that won't work at all with 256 MB modules. There appears to be no way to know in advance whether a particular iMac will work with a certain sized memory module.

Click to expand...

Yeah I fixed the HD problem, the system only boots it if set to master, not CS. As for the RAM it doesn't make sense. I understand that a 512MB chip isn't compatible, but it was reading 256MB when that chip was in there, so you'd think that by adding a 256MB chip, it would take in the full 256MB, but it only reads half (128MB). I'm getting 192MB right now (64MB bottom, "128MB" top). There isn't much I can do I guess, I have four PC133 256MB chips and none of them are registering the full 256MB when installed. I'm running OS X 10.2 and it's running fine right now.