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chawkie 04-12-2007 03:10 PM

Mac Pro Memory Help
Hey guys,

I am having some serious issues with the new RAM that i installed on my Mac Pro. Basically, I purchased 2 2gb sticks off of eBay (different manufacturers...long story) and when I initially installed them, they worked fine (came up as 5GB total on System Profiler).

Now, less then a week later, I happened to check my System Profiler, and it said I had 3GB of RAM installed. I thought maybe one of the sticks had gone bad, but instead, it seems to be reading both new sticks as 1GB sticks instead of 2GB sticks.

I ran the hardware checker on the install CD and everything came up fine. I tried switching both the top and bottom memory boards as well as the slots for the RAM and nothing changed. I am currently running Memtest from the command line (logged on in Root mode) and everything appears fine.

Does anyone have any suggestions? Any help would be greatly appreciated.


Brown Study 04-12-2007 03:30 PM

I found an article on Macworld that lists a bunch of RAM caveats for the Pro, though a lot of them involve the maxed-out install. But there's this:

The Mac Pro ships with 1GB of RAM, in the form of two 512MB modules. But those arenít just any old memory chips. For the first time, Apple is using Fully Buffered DIMMS, or FB-DIMMs.
And this:

With all third-party RAM, itís best to purchase modules that specifically support your system. And in the case of the Mac Pro, thatís not just a recommendationóitís a requirement. Apple cautions that installing FB-DIMMs that donít have sufficient heat sinks can cause louder fans and slower memory chips. Itís also a good idea to buy RAM that comes with a lifetime warranty, in case of any problems.

chawkie 04-12-2007 03:42 PM

Yeah I am sure that these are supported...they have full heat sinks...this is just really weird.

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