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Issues after 10.8.2 with Maximum installed RAM

After updating my Mac Pro to 10.8.2 I have discovered that it can no longer boot with more than 64GB of RAM, I had 128GB of ram installed and after some testing I've found that if I install 64GB it books ok, but any more it attempts to boot OSX then Halt.


Was this on purpose? when I was running 10.7 OS X claimed it could only see 96GB of RAM, but when 10.8 and 10.8 came around it updated to 128GB.


Now at 10.8.2 I get some really bad screen errors and the Mac Pro seems to halt, wont reboot when I've got 128GB of RAM installed.

MacBook Pro, OS X Mountain Lion (10.8.2)

Posted on Sep 21, 2012 3:48 AM

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Posted on Sep 21, 2012 5:50 AM

Ask the RAM vendor if they have done any more testing and had other customers report this.


check www.macperformanceguide.com


Maybe Apple didn't do enough testing, or maybe the spec were changed or tightened in the OS.


They are all biught as a set, one source and same batch...


I asked someone else to reduce half, from 96 down to 48GB and that alone wasn't working.

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Sep 21, 2012 5:50 AM in response to JuiceDanger

Ask the RAM vendor if they have done any more testing and had other customers report this.


check www.macperformanceguide.com


Maybe Apple didn't do enough testing, or maybe the spec were changed or tightened in the OS.


They are all biught as a set, one source and same batch...


I asked someone else to reduce half, from 96 down to 48GB and that alone wasn't working.

Sep 21, 2012 7:09 PM in response to The hatter

I sent an email to OWC and this was their responce


Looks like you're not alone, not sure if that's comforting or not... Looks like a lot of mac pros are suffering from hardware incompatibilities, not just RAM over 64GB. Here's my current list of issues I've come across:


*Not being able to boot with more than 64GB of ram

*Video card drivers needing to be reinstalled.

*Certain video cards failing

*Slow network speeds.

*Running Virtual Box 4.2 under 10.8.2

*Fans going full blast for no apparent reason

*GTX 550 Ti sleep issues.


I'm sure apple will address this issue quickly.


Sincerely,


OWC Tony

Technical Customer Service Representative

Other World Computing, Inc. (OWC)

OWC.net, Inc.

I think 10.8.2 has some hidden surprises.

Sep 26, 2012 11:26 PM in response to JuiceDanger

I found the answer in another thread here. It seems that the ATI driver in 10.8.2 can't handle 96GiB (or more, I expect, but that's all I have). It does work with 80GiB, so pulling DIMM 3 is sufficient to make it work. Pulling DIMM 7 works but complains about a suboptimal RAM configuration.


Only the display is screwed up; you can still access it via ssh or file sharing from another machine (if enabled).

Issues after 10.8.2 with Maximum installed RAM

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