PowerMac G5 1.6 Memory Slots

kpeterk said:

I recently purchased a PowerMac G5 1.6. My system has 8 memory slots (2 banks of 4). I was under the impression that the PowerMac 1.6 systems only had 4 slots total (2 banks of 2)? Someone please enlighten me...

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Are you completely sure you got a 1.6 GHz PowerMac G5? Go to the Apple menu and then to About This Mac and see what how fast the processor is. It should tell you right there.

According to Apple's website a 1.6 GHz PowerMac G5 should only have 4 DIMM slots, only expandable to 4 GB. If it is a 1.6 GHz G5 then I would think that someone at the assembly plant screwed something up. As long as it works then I wouldn't say anything. If you got a 1.8 GHz for the 1.6 GHz price then I really wouldn't say anything! :-D

kpeterk said:

Yes, I'm positive. Apple menu says 1.6 GHz. I ordered it through Apple refurbished. I wonder if I got a 1.8 mainboard with a 1.6 GHz cpu? I know that the 1.8's have PCI-X slots. How can I tell if I have PCI or PCI-X slots? They also sent me double the memory by the way....

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There have been reports on Apple's own discussion forums of the same thing happening with another G5 1.6 owner. It looks like Apple is refurbing returned single 1.8 models as 1.6 models...hence the extra 4 memory slots. I don't think you can tell what type the expansion slots are by checking the system profiler. I'm not sure if there are any physical differences either...I'd need to check the PCI/PCI-X specification to see what it called for with regards to the physical dimensions and appearance of the slots themselves.

Not a bad score though! The number of RAM slots is probably the biggest complaint levelled at the 1.6GHz G5 (apart from the dollar/speed ratio), but Apple seems to have solved that problem rather nicely for you. If you get any further insight into the actual identity of the board you have (perhaps the system serial number may provide a clue as to the original CPU speed of your system board?), let us know. Your discovery (and the previous one reported on Apple Discussions) seem to indicate that the G5 CPU modules may be relatively interchangeable between the different motherboards, which hopefully means that CPU upgrade modules won't be totally impossible for 3rd party manufacturers to produce in the future.

I wonder how long ago kpeterrk purchased the Mac? I had seen a report that they were going to a single motherboard so perhaps that new motherboard is showing up in recent macs?

Problem is, will the 1.6ghz module run 8GB of ram? are there bandwidth issues/bus etc - is the ram PC3200 like on the 1.8+ or are they PC2700 like on the 1.6?

kpeterk said:

I purchased the machine about a week and a half ago. I did do some research into what PCI-X slots look like and it looks like that is what is on my board. The thing that puzzles me is that it shipped with PC2700 DDR memory. I thought the 1.8 boards only supported PC3200 memory? In any case it seems to be working fine. I'm not complaining....

Here is what the board says above the barcode:

"KD3340G5ZQ6DB * 630-4847 Q37 MLB BETTER"

Anyone have any idea what board this is?

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You can probably put PC2700 RAM in a PC3200 Slot. It will just run at 333MHz instead of 400 MHz. If you have a friend with a PowerMac G5 with 400 MHz DDR RAM see if he/she will let you borrow a stick and see if it will in fact take PC3200 RAM.