I've got an early-2009 8-core Mac Pro, currently equipped with 8GB of RAM (four 2GB modules). I've ordered 16GB of additional RAM (four 4GB modules). Does it matter how I arrange these among the eight slots?
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Mixed-sized DIMMs - layout?
- Thread starter CaptainJeff
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As to what I know, each CPU only has access to one of the 4-slot sets.
Assuming this is correct, I'd go with 4422 in each 4-slot set.
http://manuals.info.apple.com/en_US/Mac_Pro_Early2009_4707_UG.pdf (see p. 41ff)
Assuming this is correct, I'd go with 4422 in each 4-slot set.
http://manuals.info.apple.com/en_US/Mac_Pro_Early2009_4707_UG.pdf (see p. 41ff)
To answer my own question, I popped these new 4GB modules in last night. I originally had two 2GB modules in each set of DIMM slots (in positions 1/2 and 5/6). I added the two 4GB modules to each set (in positions 3/4 and 7/8).
Sure enough, the memory slot configuration tool popped up, telling me I had a non-optimal configuration. OSX wanted the 4GB modules in the first slots in each set and the 2GB modules in the second pair of slots. So, I ended up swapping everything with two 4GB modules in the first slots (1/2 and 5/6) and the two 2GB modules in the second slots (3/4 and 7/8) for each set. Boot it up and the memory slot configuration tool informed me that I was now optimal.
Sure enough, the memory slot configuration tool popped up, telling me I had a non-optimal configuration. OSX wanted the 4GB modules in the first slots in each set and the 2GB modules in the second pair of slots. So, I ended up swapping everything with two 4GB modules in the first slots (1/2 and 5/6) and the two 2GB modules in the second slots (3/4 and 7/8) for each set. Boot it up and the memory slot configuration tool informed me that I was now optimal.
