Memory compatibility questions for new iMac.

N

namdnas

Registered
I am wondering if I can use a 512MB PC-133 DIMM from my 533MHz Digital Audio PowerMac in the Apple slot of the new 800MHz iMac that I've ordered. In Apple System Profiler under OS 10.1.2 it lists as PC-133 CL3 SDRAM. From what I have been able to piece together from some posts, it may work fine in a derated state in the iMac, but I want to be sure.

Also, will the following 512MB SO-DIMM module work in the user slot of the same iMac? It is Kingston part #KVR100X64SC3/512

It has the following specs;
144 Pin SODIMM (Small Outline DIMM) using gold contact fingers and requires +3.3V. 64Mx64 (512MB), CAS Latency 3 (CL3), SDRAM (Synchronous DRAM), 100MHz memory module

It is CL3 as well, but again, I am wondering if this will derate to work in slower busses.

I am trying to get this new iMac up to 1GB as cheaply as possible and this info would help me quite a bit.

Thank You.
 
Yep, I think both of them will work in the new iMacs. To be 100 % sure, you can ask Apple, I guess they're willing to help :)
 
As I understand... there is a standard DIMM slot in the inner workings... but I'm not sure how accessible it is. There IS a SODIMM slot immediately accessible from under the base plate, next to the airport card. I don't know if there's a 'power user' accessible slot later on. They probably went with the sodimm's as the 'user accessible' ram slot because of form factor and to make it more standardized with the iBook/Powerbook. I'd be very interested to see just how accessible everything is...
 
To make things more confusing, I have read the following. at the Apple developers site here which states that both the DIMM and SO-DIMMS need to be PC-133. On the other hand, anothe part of the iMac spec site verifies that these units interface the Maxbus interface at 100MHz.here .

I hope that if they use a 100MHz bus, that we can get away with PC-100 RAM...

So, at the end of the day, I guess I'll wait, and see what happens when it finally ships.
 
It doesn't make sense that the new iMac would REQUIRE PC-133 RAM. I believe that it should take both PC-100 and PC-133 RAM. However, the standard DIMM slot is basically NOT user accessible, and from what I've read, both voids the warrantee and makes some shock-dissipating padding or such in need of replacement. So I definitely DO NOT recommend relying on putting this in. You MAY be able to bring your RAM to an Apple store when you buy your iMac and have them install it for you, but don't count on it (that would be awesome service, though).

Maybe I'll go over soon and ask them about this at the Genius Bar. I needed to go over and complain about them not including a replacement set of earbud covers with the iPod which I so recently lost. :(
 
The PC-100 SO-DIMM I mentioned earlier works just fine. Also, the 512MB DIMM that I installed in the Apple-only slot works great too. They are both reported in Apple System Profiler as PC-100 SDRAM 322. I would go with the cheaper memory if you can get a deal.

PS I reapplied thermal grease at the thermal junction in the unit using Radio Shack Part #276-1372 Heat Sink Compound. Not reapplying this could be a real problem, so I suggest picking up a tube if you're going to crack open the base of your unit (past the access to add the SO-DIMM, which is user serviceable).
 
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