G5 memory problems

This is my first entry to the forum!

I have a G5 powermac single 1.8 GHz processor which has 4 x 128 Meg of memory that it was shipped with.

I seem to be having a problem with upgrading the memory, I want to add an additional 1 Gig of memory bringing the total to 1,25 Gig ( i am taking 256 out and putting in 2 x 512) but the machine will not accept the new memory.

The error I receive is two beeps on startup which I believe signals incompatible memory.

I thought ok , I will try different memory as this is jst generic so I bought 2 x 512 kingston memory (and i know this is the right stuff as i used the online configurator) still the same problem??

I was lucky enough to be able to return the memory and try the reccomended memory from pc world (same spec as previous sticks) and again the same error occured???

So now im thinking this is a hardware error , iused the hardware test disk that ships with the G5 and this says that everything checks out ok including the logic board.

Now im really confused, I knnow all the memory was the correct specification but the hardware checks out ok.

Does anyone have any ideas? could it be firmware, according to my Mac the firmware is version 5.2.2. (although i cant find this on Appls website) i tried installing a previous version of the firmware but im not allowed to,all software is upto date.

Any help or suggestions would be a massive help.

You didn't post it, what kind of RAM are you putting in?
The Power Mac G5 you have should take PC 3200 (DDR 400) RAM. Is this what you are putting in? If not, then it is likely not going to recognize it. It could also be that you are just using bad RAM sticks...do they work in other computers?

the powermac is extremely fussy with what ram it accepts. when i first got mine, i had ordered 2 1gb memory sticks online. The powermac would not accept it. The key is that if your not buying paired sticks, it will need to be very high end memory. Just because it is the same manufacturer, and capacity, does not mean they are "paired" Compusa sells memory that is actually paired especially for powermacs. Www.NewEgg.com sells "corsair value select" 1 gb (2x512) that work great in the powermac. it is very reasonably priced as well.

Also are you are you installing them in pairs? The G5 Powermacs have to be in pairs. Which two sticks did you take out when you bought the new RAM? I found out a long time ago the matched pairs have to go into the correct DIMM slots or it will do exactly what yours is doing. If I remember correctly the Single 1.8 G5 took 4 memory sticks. Going now to find a url that shows which DIMM Sockets each matched stick should go into. This will show you which slots the pairs have to be installed into.

http://manuals.info.apple.com/en/Memory.pdf

Hope all this helps.

Like Menace stated, they have to be either matched pair of RAM or very high quality PC3200 DDR.

Sorted, after chatting to apple "technical support" they confirmed that the first two pairs of memory need to be installed in the two middle Memory expansion slots, then the next two pairs need to go in the outer expansion slots.
I am a switcher, I have worked on pcs where the dual channel memory needs to be installed in the first and third, second and forth slots but never like this!!

I am learning stuff about the Mac world all the time

Thanks for your advice.

Glad you got it all working. Enjoy your Mac!!