Mac Pro '08 report incorrect total RAM

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Mac Pro '08 report incorrect total RAM

I just got 3 new '08 Mac Pro for some collegues. Standard models with 2 x 1GB i A1 and B1. I pluged in additional 4 x 2GB i A2, A3, B2 and B3. It shows only 6GB in total - not recogn. A2 and B2.

Then I plugged in 4 x 2GB only i A1, A2, B1 and B2 - every things okay. - then adding the 1GB i A3 and B3 - no go :o(

Then I took 6 x 2GB from 1 to 3. A3 and B3 not showing. Then the original 6 x Apple 1GB same config - still no go for A3 and B3.

Conclusion: Max. total for me = 8GB. If I mix: 2 and 4 are not shown if 1GB is in 1. If 2GB is in 1 and 2, and 1GB i 3 - the 1GB does not show. Any suggestions or similar experiences? Regds. Hennekem

Mac Pro 2008 - 2.8 DP QUAD, Mac OS X (10.5.1)

Posted on Feb 14, 2008 12:11 PM

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Answer 1

Feb 14, 2008 12:33 PM in response to hennekem

See pages 46 and 47 in the User's Guide that came with the computer
<http://manuals.info.apple.com/en/Mac Pro_Early2008.pdf>
The 1GB chips go in the first two slots of the top card. The 2GB chips go in the last two slots of the top card and the first two slots of the bottom card.

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Answer 2

hennekem Author

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Feb 14, 2008 12:45 PM in response to Malcolm Rayfield

Doh, great help Malcom. Thanks a lot. You opened my eyes for the manual ;o)

- thanks again.

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Answer 3

cx12

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Feb 14, 2008 3:27 PM in response to hennekem

I believer you configuration is wrong. You need to install in pairs. 2gb kit on A1+A2 4 gb kit on B1+B2 and so on .

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Answer 4

rob_ART

Level 2

426 points

Feb 14, 2008 4:26 PM in response to hennekem

A better way is to put 2 x 2GB in slots 1&2 of riser A,
2 x 2GB in slots 1&2 of riser B,
and 2 x 1GB in slots 3&4 of riser A.

We tested that arrangement with the 64 bit parallel multi-threaded version of STREAM memory test. It gave a faster memory transfer rate that just 4 x 2GB FB-DIMMs, but not quite as fast as 8 x 2GB. And you can see the full 10GB.

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