Powermac G4 memory problems

I have an older Powermac G4 that was given to me. It is a digital audio, 533MHz. When I recieved it, it had 512MB of ram installed with two 128MB sticks and a 256MB stick. I installed Leopard using the Open Firmware trick.

I pulled two 256MB sticks out of comps that were laying around, the memory is known to work. I know that the DA G4's car use 1.5GB of ram. I was planning on running 768 with the three sticks.

The problem is that with any two of the three 256 sticks, in any two of the three memory slots, the PC will boot and run fine. Any combination of any two sticks, in any combination of any two slots will work.

I don't know if this is a problem with the pc not liking over 512MB (didn't know if that was a issue) or if there is a problem with the memory itself. I wouldn't think there would be a problem with the memory as it works fine in any combination of two, and it all works in my PC's of similar setup (Old Dell GX150's)

Any help or insight is appreciated, this is my second Mac and I am not very familiar with the hardware or software of the PowerPC era.

Thank You!

Something similar happened to me but I had some spare and managed to get 1.5gb in to my 1.5ghz Fastmac Quicksilver. I've said it before though, I feel Leopard runs sluggish compared to when I had 1 or maybe it was 1.25gb of ram. All I had running yesterday was Firefox, iTunes converting and it felt sluggish.

My point to all this is Leopard probably needs more ram than you put in - good luck.

Well if it works ion the PCs that is not a good recommendation. The G4 requires low density modules and most PC memory is high density.

To get anything like a decent performance from Leopard install 1.5GB memory. Here is a link to the Apple compatible memory. Use it for specs and shop around if you wish:-

Memory Upgrades for your Apple PowerMac G4 Digital Audio 533MHz (2001) at OtherWorldComputing.com

Rule of thumb the older the machine the dearer the modules.