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6, 12, & 24 GB of RAM on new mac pro towers
The config guide states that on the new 2010 mac pro towers, you should have 6, 12, or 24GB of ram, and specifically that 16 and 32 are not good.
Since the new mac pros have 8 slots for ram, the suggestion is that your should have one of the following:
6x 1GB
6x 2GB
6x 4GBNever using the 7th and 8th slot for RAM…
Is this correct? I have never heard of this in any other application. Am I correct that the suggestion is to never use the 7th or 8th ram slots, and that the above 3 configurations are the only supported RAM configs?
Also, is there any more detail on why this is the case? I am very curious!
Thanks!
-Nat Jencks -
7 Replies
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This has to do with the number of “memory channels” inherent in the Nehalem and Westmere processors. I know that the Nehalem’s used in the Mac Pro’s have 3 memory channels per processor (as I understand it). So, for optimal memory handling RAM needs to be installed in matched, congruent sets.
I know, it broke my heart to leave an empty DIMM slot! I installed 6x 4GB DIMMS for 24GB of RAM. This was the most cost effective config. Using the 8GB DIMM’s were too rich for my blood.
I’m not an expert on this stuff, but this is how I understand it. Here is a link to the wikipedia page for the Intel Xeon processor line. It is a little geeky, but helpful.
https://en.wikipedia.org/wiki/Nehalem_%28microarchitecture%29
– Jonathon
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I just built my 12 core with x4 8gb owc ram sticks although it’s not recommended will I still be able to use resolve?!
please god let it just be a minor performance thing… -
Buy two more 🙂
A slice of color…
DaVinci 7.0.3
Dual Xeon 2,4
OSX 10.6.5RAM 6 GB
RAID 8TB intern
Extern 6TB
GTX 285 / GT 120
WAVE -
It should run, but you will take a performance hit. Not sure how much? It may effect realtime playback. I think that BM has tried to optimize for max performance because they are pushing the systems to the limit with regard to moving data around.
The performance hit will probably be more noticiable if you are using formats that need to be decoded on the CPU… pro res, DNX, r3d (w/o RR).
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for people who take advantage of 64 bit (C4D, CS5, fcp eventually) this is a brutal issue – I wonder if a future update for osx could somehow fix this issue?
thanks
sean -
Of course, if he buys two more 8GB chips fora a total of 6x8GB (48GB), that config isn’t officially supported either 🙂
This whole thing of only supporting use of 6 out of the 8 ram slots is really kind of odd.
I would have thought that if adding ram into the additional 2 slots actually slowed down memory performance, apple would have only included 6 slots for RAM…
@Johnathan Lee, yes, it seems like 6x4GB for a total of 24GB is the sweet spot if you are aiming to follow this rule of using 6 out of the 8 slots.
best
-Nat
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Hi Nat,
Some applications require a huge amount of RAM but don’t have the real time requirements of video so memory optimization is not so important. For other applications like Resolve, memory speed is much more important. Our recommendations may change with each new generation of Mac Pro as the memory architecture can change over time. For example, 8 GB of RAM is a recommended configuration in the Early 2008 Mac Pro series.
Regards,
Luke Maslen
Blackmagic Design
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