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iMac G3 RAM

Arkious

Arkious

macrumors 6502a
Original poster
Mar 14, 2011
583
0
Newcastle, UK
Hi All,

Just a quick question regarding RAM in an iMac G3 Slot-Loader.

I have recently purchased some cheap RAM, but it seems to be giving me a few issues. Firstly i couldnt install OS X 10.3 without crashing, but the apple site said revert to standard RAM and it should be ok, which it was. so i put the other RAM back in after and now it seems to occasionally crash and make a bit of a buzzing sound. I know cheap isnt best but is this a common thing or just iffy RAM? i didnt really want to spend much money on this thing, just wanted the best i could out of it so got 1GB of RAM, a nice new quiet HDD and an Airport card.
 
I found some Crucial RAM for £15 so going to buy that instead, this other ram is very unstable! I'm just hoping to pick up a DVD drive for it too and then I'm sorted :-D
 
Slot loading G3 iMac drives are hard to find and expensive. They don't take regular PATA slot loading drives. Instead Apple rotated the standard connector 180 degrees to make all other drives not work without a new adapter board. Only slot loading G3 iMacs and G4 Cube use this rotated not quite standard optical drive.
 
Will the imac G3 400 support 1 gig of RAM?

The specifications state the limit as 512k. Assuming good quality RAM is this a safe practice. I can't believe that this machine has been working for 13 years with only a new HD?
 
You can hack other slot-loading mechanisms into service.

When buying RAM for Apple HW, memory timing and voltage are critical, and even when RAM meets a spec, such as PC2700, it may not work on Apple HW.

I certainly don't advocate spending more on RAM than it would cost to buy a newer system, with as much memory in it already. :/
 
Timing and voltage is not critical for PowerPC Macs, nor most Intell based Macs. With PowerPC Macs the density is critical. Always get low density ram. Never get high density or it won't boot or it'll show only half of the stick's actual capacity.
 
Intell said:
Timing and voltage is not critical for PowerPC Macs, nor most Intell based Macs. With PowerPC Macs the density is critical. Always get low density ram. Never get high density or it won't boot or it'll show only half of the stick's actual capacity.
Click to expand...

Tell that to a Dual-G5. Generic, low density 2.6V PC3200 DIMM sticks won't work in a Dual-G5, that calls for PC3200 2.5VDC. They cause the system to go into diagnostics mode, and flash 'bad RAM'.

That is either a timing (CAS latency), or power problem, using NECC DIMMs.

You might want to read about RAM requirements, before commenting further about what requirements exist for memory modules on Apple HW:
http://guides.macrumors.com/Buying_RAM

Some systems are far more touchy than others, but timing/latency, and voltage are always important concerns. Often, generic memory will have a very high latency ra5ing, which causes the NWR RAM diagnostics to halt, and show a fault.

G3 systems are less of a problem, but you should always work with branded RAM, and note the types used in your model (by IC ident), and compare that to anything that you wish to install.
 
My personal G5 a dual June 2004 model, as well as the ones where I work, all use random mismatched generic PC-2700 or PC-3200 sticks of varying voltages, latency, and ECC abilities all from eBay and other used parts retailers. Not one problem. I've had more problems with eMacs than I've ever had with any G5.
 
random that this got brought up again :)

i actually went ahead and got some crucial stuff, worked great until i went to turn it on the other day and it was dead as a door nail haha (not been used in a couple of months). not had the time to investigate it yet but it sits there on a white screen.
 
Meanwhile, I have trays of PC2700, and PC3200, that if I put even one stick in a dual-G5, the system halts, and flashes at me. Most of that is even name-brand stuff, like Kingston and Crucial.

Goodness knows what such a mismatch is doing to degrade your system performance: Using PC2700 slows the entire bus down to that clock speed, and general mismatches increase overall system latency.

Just because your system will boot and doesn't crash, doesn't mean that your situation is either typical, or ideal. It's actually a very bad idea; and using the proper type of memory, including latency, clock speed, EEC type, and keeping a general, overall harmony across your bus will greatly improve your overall system performance.

Is your G5 a four-socket, or an eight-socket model? If it is the four-socket, that may have looser tolerance than the eight-socket mainboards, which account for almost all of my G5 towers. Of the group, I have only one four-socket version, plus some G5 XServes, that use an altogether different RAM spec.
 
The PC2700 is only used in the slower 1.6Ghz and 1.8Ghz machines. 2.0+ machines won't see it. The mismatched latency and ECC has no performance degradation and it not causing harm to any of the machines components. This is a varity of G5 machines from nearly every revision and model except for the G5 iMac and late-2004 1.8Ghz G5. The memory is all within spec and functions correctly with no problems for any of the systems that uses it. Proclaiming that one should only use the fancy strict memory is similar to stating that a simple Honda or GM vehicle only use the highest octain fuel when it offers no gain to performance or vehicle longevity.
 
Intell said:
The PC2700 is only used in the slower 1.6Ghz and 1.8Ghz machines. 2.0+ machines won't see it. The mismatched latency and ECC has no performance degradation and it not causing harm to any of the machines components. This is a varity of G5 machines from nearly every revision and model except for the G5 iMac and late-2004 1.8Ghz G5. The memory is all within spec and functions correctly with no problems for any of the systems that uses it. Proclaiming that one should only use the fancy strict memory is similar to stating that a simple Honda or GM vehicle only use the highest octain fuel when it offers no gain to performance or vehicle longevity.
Click to expand...

Ah, I see why it's working for you. The pre 2GHz G5s have a different SDRAM controller: The 2GHz -> 2.7GHz are far less flexible, and all of my G5s are 2GHz and later. I think that the MMC in the earlier G5 systems calls for PC2700 in any event, so your PC3200 RAM is downstepping to the slower clock.
 
You're misreading what I wrote, I have used mismatched ram in every G5 except for the G5 iMac and late-2004 1.8Ghz model. That means that everything else, from a 1.6Ghz to a 2.7Ghz model I maintain all run mismatched ram. Furthermore, the memory controller in all AGP PowerMac G5s is the same except for the late-2004 1.8Ghz model. The only difference between all the APG models (expect for the previously mentioned 1.8Ghz model) is its speed ratios. Everything else from the codename to the revision number is the same.
 
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