Which DIMM slots for 6GB RAM upgrade

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Which DIMM slots for 6GB RAM upgrade

I am not sure if it makes any difference in a Santa Rosa macbook pro whether you put the 4GB RAM chip in the top DIMM slot or the bottom DIMM slot when upgrading to 6GB of RAM. I had heard that bigger chips must be configured properly in a mac pro to get optimal use of the RAM. I have looked all over for an answer for this and cannot find any information about this anywhere. Any help would be appreciated.

Macbook Pro 2.4g Santa Rosa, Mac OS X (10.5.7)

Posted on May 16, 2009 7:28 AM

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Answer 1

Allan Jones

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May 16, 2009 8:03 AM in response to jmemije

I'm seeing mixed messages about getting a Santa Rosa to 6GB RAM. Several RAM vendors say it works but some very knowledgeable people in these forums with years of MBP experience say that the 6G option started with the later Penryns. I'd hold off ordering the RAM until you make certain it will work, or at least until the price of a 4G stick goes down. WAY too expensive right now.

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Answer 2

jmemije Author

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May 16, 2009 8:09 AM in response to Allan Jones

Thanks for the quick reply Allan. Actually I already purchased the RAM from OWC. The 6GB kit was less than $200. My Macbook pro sees all the RAM and programs like Photoshop and Lightroom running together are definitely taking use of it. I was just wondering really if anyone knew if it matters which DIMM each chip should go to...

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Answer 3

Allan Jones

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78,266 points

May 16, 2009 2:53 PM in response to jmemije

A second test to make sure all the RAM is properly recognized is to open Activity Monitor and see what it says. Click the "System Memory" button and, from the lower pane, add the numbers for "Free" and "Used." If the RAM is fully recognized, those entries should add up to close to 6GB. Example: my Santa Rosa has 2G installed. "Free" shows 1.45G (1450MB) and "Used" shows 542MB. That adds up to very close to 2G.

It's been a long time since Mac RAM was slot-sensitive. I don't think it matters on the current machines.

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Answer 4

jmemije Author

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May 16, 2009 4:38 PM in response to Allan Jones

I have 4.38GB Free and 1.61GB Used. Maybe it does not matter which DIMM it is in on a Macbook Pro. I have read optimal configurations on Mac Pro's so I figured there maybe something to it... 6GB seems to be just fine on this machine. Purchased my RAM from OWC. Many have had a great experience wit this configuration. I definitely needed it running CS3 & Lightroom together at the same time. Things are definitely humming along...

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Answer 5

Allan Jones

Level 9

78,266 points

May 16, 2009 9:26 PM in response to jmemije

Thanks so much for the info. I believe this is the first time someone here has verified what the RAM vendors have been saying about the Santa Rosas since the 4GB sticks became available.

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Answer 6

Jun 12, 2009 12:44 AM in response to jmemije

I have this same question. I have a late-2008 unibody MBP 15, and 6GB of RAM. However, I have observed some instability with 6GB (kernel panics). I'm not sure what to point the finger at. I ran memtest86 overnight without any errors. The memory is Corsair. So, I'm not even sure it's the memory causing the issues.

Most often the kernel panics are from the mdworker or Parallels processes -- both of which are notorious for causing kernel panics.

Anyway, I was also curious whether anyone else has speculation on "Slot 0" vs "Slot 1". So far, I've only run it in "Slot 1". Currently, I've yanked the 4GB DIMM from the MBP and am running back at 4GB (2x2GB).

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