answer from OWC : 128GB is the maximum currently addressable by this system. Would be nice if 256GB was supported, but nothing beyond 128GB is addressable with current Apple OS X/Firmware release and that isn't likely to change for this system - but we are always watching.
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256GB RAM in old MP?
- Thread starter fhenry
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Max RAM is 48GB for single CPU 4,1 and 5,1.
See this thread:
https://forums.macrumors.com/threads/1500199/
...and follow the links from post #2.
Yes, I read that right after I posted. However, note this from post #11 in that thread:
"If all 4 sticks of 16gb are present it locks during boot with black screen with sparkly white Apple. May get a x56xx and verify this other theory."
and this from post #12 of the same thread:
"I can confirm that 4x 16GB works in single CPU 5,1 using Dual QPI CPU.
I tested X5650, because I only own these ATM.
In mine memory runs @800 MHz, because currently I have 3 sticks of 1066 and 3 sticks of 1600 RDIMMs, so I had to combine them in one or another way and it always yields 800 MHz.
That's only for testing purposes, because 48GB is enough for my use and I prefer to have triple channel over dual channel mode."
I also saw your post in that same thread, saying you could confirm 64GB with a similar setup as described above. Did you also see a drop in RAM speed to 800 mHz?
All this is really academic for me because I'm using a w3680 so it's 48GB for me (or apparently 56GB per what MacVidCards said in post #1).
"If all 4 sticks of 16gb are present it locks during boot with black screen with sparkly white Apple. May get a x56xx and verify this other theory."
and this from post #12 of the same thread:
"I can confirm that 4x 16GB works in single CPU 5,1 using Dual QPI CPU.
I tested X5650, because I only own these ATM.
In mine memory runs @800 MHz, because currently I have 3 sticks of 1066 and 3 sticks of 1600 RDIMMs, so I had to combine them in one or another way and it always yields 800 MHz.
That's only for testing purposes, because 48GB is enough for my use and I prefer to have triple channel over dual channel mode."
I also saw your post in that same thread, saying you could confirm 64GB with a similar setup as described above. Did you also see a drop in RAM speed to 800 mHz?
All this is really academic for me because I'm using a w3680 so it's 48GB for me (or apparently 56GB per what MacVidCards said in post #1).
For w3680, yes 48gb is best for you sice you want triple channel.
Mine with x5670, all 4x16gb at 64gb reports 1333mhz.
You must have used UDIMMs if so. I found that UDIMMs do not show speed drop in ASP and RDIMMs do.
I believe that 32GB modules should work as well, so 128GB with X CPU should be possible. But who needs that much in single CPU machine...
You must have used UDIMMs if so. I found that UDIMMs do not show speed drop in ASP and RDIMMs do.
I believe that 32GB modules should work as well, so 128GB with X CPU should be possible. But who needs that much in single CPU machine...
I bought 8 sticks of this. It's Registered, RDIMM if thats what you mean.
http://www.kingston.com/us/memory/search/?partid=KVR13R9D4/16
You can't mix with any other sticks, as I tried some other brand or even Kingston, as long as not CL9, or even mix with 1.35v sticks, it will reduce in reporting speed. So rule of thumb, same part number for all stick in memory pool.
If 128gb is possible, I think some people might want to do it, because the OP is asking 256GB. Obviously he is asking for dual CPUs. for One CPU, 128GB might be achieved for some psychological therapy.
But saw one post referring to OWC that OSX address limit to 128GB. Perhaps that's another myth. Since none of our forum users tested....:
I see it now... It's matter of ranks, not registered/non-registered. So Umbongo was pointing in right direction in another thread, kinda right
I mixed 4R RDIMMs with 2R ones and got 800 MHz. All UDIMMs I had were dual ranked. I'm waiting for another couple of 2R RDIMMs, so I'll be able to test this in my MP. Thanks for clarification.
Regarding 128GB in SP: I found 32GB 1066 MHz modules on my local market, but price is rather high, equivalent of $800/piece. Not gonna pay such money just for testing purposes
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