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Compatible RAM for Power Mac G4 MDD

B

bocktacular

macrumors newbie
Original poster
May 21, 2006
11
1
Hello!

I wanted to see if I could pick brains on a RAM issue. I have been recently tinkering around with converting my old Power Mac G4 into a file server. I recently tried to tackle upgrading the RAM from the original 1GB (2X512MB DIMMs) that came with the machine to its 2GB max.

I first tried purchasing RAM from Other World Computing (OWC). I purchased four new DIMMs (4X512MB). None of them worked, which was bizarre. I installed all four, and heard the three beeps indicating the RAM issue. I attempted to clean the RAM module contacts as advised by OWC, with still no luck.

And then I tried eBay. I found four Kingston modules (again 4X512MB) that appeared to be the proper specification for the machine - same types of chips as the originals (DDR. Installed the four, machine starts up, and the RAM is recognized through System Profiler. However, I begin to experience Kernel Panics within about an hour of the machine being turned on. I changed two of the modules back to the original ones included with my machine. The machine would stay active longer, but would eventually crash over a longer period of time.

So, I'm back to my 1GB and my machine seems to be stable again. I would still like to upgrade to 2GB, as it would be more ideal for the machine if I am using it as a file server. I'm beginning to think that the Power Mac G4 is just super cranky about the type of RAM it can use.

Any thoughts or experience on this? Is there a certain type/manufacturer of RAM that works best?
 
My own MDD is weird about its ram. For some reason, it'll start when I have it open, but when I close it, nothing. Once I wiggle the ram, it'll start again. This does make opening it back up kind of a pain, but I can generally get it to work. It came with a bunch of unrelated ram and all of it works, it seems to have more to do with how loose the ram is.

That could just be me, but I haven't seen nearly as much about the MDD as about other G4 systems.
 
Both of your problems are just weird.. I know G5s and B&W G3s are really particular about RAM, but I haven't heard of G4 desktops doing this sort of thing. None of mine have ever had a problem that I can remember.

I would advice both of you to run an Apple Service Diagnostic.

@bocktacular I only buy RAM from DMS as they are extremely good at acquiring ancient RAM for ancient systems, and have a great warranty. I have only ever gotten one bad stick and they replaced it immediately. Though, OWC RAM should absolutely work, albeit extremely overpriced.
MMDs will also take 1GB sticks, but it'll only address 2GBs should you install more. Probably best to run x4 512MB, but if you have 1GB sticks laying around already its an option.
 
Project Alice said:
Both of your problems are just weird.. I know G5s and B&W G3s are really particular about RAM, but I haven't heard of G4 desktops doing this sort of thing. None of mine have ever had a problem that I can remember.

I would advice both of you to run an Apple Service Diagnostic.

@bocktacular I only buy RAM from DMS as they are extremely good at acquiring ancient RAM for ancient systems, and have a great warranty. I have only ever gotten one bad stick and they replaced it immediately. Though, OWC RAM should absolutely work, albeit extremely overpriced.
MMDs will also take 1GB sticks, but it'll only address 2GBs should you install more. Probably best to run x4 512MB, but if you have 1GB sticks laying around already its an option.
Click to expand...
Well, there are 3 different brands of ram in my system, and the two matching sticks are particularly loose. When I need to get it to boot, I just wiggle one and press the power button. So, I'm going to assume this isn't really a picky ram issue. I don't really know what the Apple Service Diagnostic would tell me, especially since I did type this from my MDD but I'll put it on the list of things to do.
 
I'm assuming, but I'm not sure. My profiler says the Boot ROM Version is 4.4.8f2.

@ Project Alice - Thank you for the tip - I'll give DMS a try. I hate to keep buying RAM chips. Luckily it's cheap nowadays for this machine.
 
Having the right type (SDRAM, DDR, DDR2, etc.) and memory speed is not all you need for a computer. Sometimes you need to have the correct chip "configuration". By that I mean chip count, layout, dual / quad / other, etc. I do not fully understand why but I can have two of the same type / speed memory with different chip configurations where one will work and the other will not. I would expect OWC and the other big name guys to know this and provide the right type for any given system but mistakes do happen.

Curious as to why you think more than 1GB of RAM would benefit a home based file server. Is Activity Monitor showing RAM constraints?
 
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I don't find my MDD (867MHz Dual) fussy about RAM at all. Currently it has a mix of Samsung DDR PC2100 256MB (stock) and Kingston DDR PC3200 256MB, PC3200 1GB, PC2100 512MB (I'm quite sure this one is counterfeit).

The problem may be at the RAM slots. Try installing just one stick and see. This is a very old computer. Solder joints may crack, contact pins may be bent or loose, etc.
 
Last edited:
repairedCheese said:
Well, there are 3 different brands of ram in my system, and the two matching sticks are particularly loose. When I need to get it to boot, I just wiggle one and press the power button. So, I'm going to assume this isn't really a picky ram issue. I don't really know what the Apple Service Diagnostic would tell me, especially since I did type this from my MDD but I'll put it on the list of things to do.
Click to expand...
ASD is not the same as AHT (Apple Hardware Test). ASD is what they used at the genius bar I believe, and other service centers. It tests more things and more thoroughly. It's probably the closest we can come to memtest86 on PPC. And it tests a lot more than the memory.
bocktacular said:
I'm assuming, but I'm not sure. My profiler says the Boot ROM Version is 4.4.8f2.

@ Project Alice - Thank you for the tip - I'll give DMS a try. I hate to keep buying RAM chips. Luckily it's cheap nowadays for this machine.
Click to expand...
I would run the tests first. I also hate buying ram constantly.

4.4.8 is the latest for an MDD I believe.
 
I am joining this thread since my questions are exactly about MDD's memory upgrades and so far I was constantly looking for the fastest and stable memory sticks I can fit in this wonderful PowerPC machine.
I literally spent tons of hours on eBay and various local and foreign hardware stores to find the fastest DDR memory modules the MDD could handle (and if possible the most stable) but in the end I found that every modules faster than 25330 (the speed reported in System Info) means both instability because the amount of heat that need to be dissipated and next to none speed increase in benchmark tests...
I have tested many 20220 / 512 Mb memory modules of different brands but every time I was disappointed in lacking of speed improvement, in the end I found that a couple of 1 Gb sticks placed in alternate rows was the best compromise in stability and performance. The fastest 1 Gb DDR memory stick I could found was a G.Skill brand with 25330 timings, the only one (well, a matching couple) faster than all the other memory modules of the same size I have around: all of them are 30330. My MDD is equipped with a double 1.5GHz G4 (overclocked from the stock 1.42 GHz speed), an SSD as boot disk and a flashed FireGL X3-256 (X800XT).
My question is: what brand/model of memory sticks would you recommend as final upgrade for speed up an MDD?
 
i have a couple of 1GB mushkin DDR-400 sticks in my eMac and i believe they are 25330. not too sure about these memory timings, but they do have heat spreaders so i am ASSUMING they run faster than conventional ram... or they are just there for show. needless to say, they go well with that system, especially at 1.92GHz. i believe there are 512MB variants of these sticks around, but i am not sure.
 
Interesting CPU upgrade for an eMac! :) I also have one 1.25 GHz overclocked to 1.50 GHz but sometimes it tends to freeze, not sure if related to memory or insufficient cooling, I will check in the near future. In my MDD I have tested four matched Corsair CMX-512-3200XL (pure 20220 timings) but they went insanely hot and after a moderate system load a crash occour. Both Geekbench and Xbench do not have revealed significant improvements over the more stable (and cool) 25330 modules. The Mushkin brand is something I was often tempted to purchase but since I am surrounded by DDR memory sticks I am waiting for first hand advices before proceeding with further purchases.
 
it's not a CPU upgrade, i overclocked the CPU to 1.92. it's only possible on the 2005 models. 700 and early 800s can go to 900, later 800s and the 1ghz emacs can go to 1.2/1.33??, usb2s can go to 1.5 (1.42 if it has an original 7447), and the 2005 can get up to 1.92. i should do another writeup on this at some point.

also i'm sure some of that RAM was not necessarily designed to run in a G4 tower. should be careful with what you buy.
 
Sometimes dealing with CL2 DIMMs results in only 3 over 4 recognized by the MDD (usually the J21 slot is the one that does not configure the memory bank) but strangely after swapping one or two modules, even if they are identical and matching quartet, all the 4 modules are usually recognized and configured, I am talking, of course of 512 Mb modules.
About your experience in eMacs overclocking, yes, I would love to read something about it, when I overclocked mine I did not touch the voltage, only the clock multiplier, maybe this could be the issue?
 
i just did a gb on my eMac running leopard and i got around 893... i think the mushkin memory may not be working so well here! i haven't put results in but also this could really just be 2.2... i've also noticed LU decomposition benchmarks are worse on 2.2.x than they are on 2.1.x. oh well, time to put CL3 memory back in! :^)

last time i did this i got 1103. used CL3 DDR-400 if memory serves me right. (no pun intended)
 
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