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ZombiePhysicist

macrumors 68030
Original poster
May 22, 2014
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I'm looking to get a good price on some 16GB memory sticks for my Classic Mac Pro, (5,1, 3.46GHz 12 core if it matters). Anyone have a good place for it?

I was hoping to get some suggestions for good memory from others here, and/or experiences. I want to get 6 sticks to bring memory up to 96GB of ram.

I found these two places to get memory:

$1179 at OWC
http://eshop.macsales.com/item/Other World Computing/1333D3X9M096/

$947.94 via Amazon
http://www.amazon.com/dp/B008542F60...UTF8&colid=ZCJYBY6EVNJM&coliid=I3P8IOY8DRFEA2
 

dlindsey100

macrumors newbie
Jul 28, 2014
18
4
Seattle, WA
I installed 48GB (3 Sticks) since that was the recommended way to do it and not have any memory in slot 4. So, for a dual CPU, I believe that the most optimum configuration would be 6 sticks (3 for each CPU) which would be 96GB ram if used 16GB sticks.
 

ZombiePhysicist

macrumors 68030
Original poster
May 22, 2014
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Thanks Demi, I ended up going with

Kingston ValueRAM 16GB 1333MHz DDR3 PC3-10666 ECC Reg CL9 DIMM DR x4 Server Memory model no. KVR13R9D4/16

I got them for between 137 and 144 a stick from both Amazon and NewEgg.

This memory works great in a 2010 Mac Pro (5,1). I usually buy from OWC but this was so much cheaper I wanted to take a chance. So a quick review, this has everything you would hope.

First, it has temperature sensors that show up in OS X if you use tool like iStat menus.

Second, it runs much cooler than the 8GB sticks I used from OWC (these run at about 125F, while OWC ran at about 150F). It ran cooler despite the OWC being lower capacity and it having the fancy heat sink things on the memory.

Third, you can run 4 of these per processor bank and it will still run at 1333MHz and not drop down in speed to 1066 like many other chips will!!! That is amazing because it basically is running better/faster than Apple said was possible.
(i.e., apple recommends you load only 3 sticks per processor bank to keep everything running at 1333MHz, and if you use the 4 slot you can expect a drop down in speed to 1066MHz, but this will run flat out so you can max memory to 128GB (with yosemite) and experience no speed decrease--I believe the latest OWC memory also lets you do this). Once I discerned you could run at full speed even using 4 slots, I decided to load up and max memory out at 128GB)​

I also ran memtest 4.23 on this, and it passed with flying colors (it takes about 4.5 hours per 48GB for a single pass of memtest so be prepared 12+hours of testing if you load up the full 128GB using these sticks).

I got 3 of these for $137 per stick on amazon, but the price went up to 160 something right after I bought it and now dropped down to 144. So the prices vary wildly and daily on this. So I bought 3 sticks on amazon and then another 6 sticks at newegg as it was cheaper (particularly without the tax hit).

Best bet for finding the best price is just do a search on google shopping for the model number: KVR13R9D4/16.

Hope this helps some others that are on the fence.
 

ZombiePhysicist

macrumors 68030
Original poster
May 22, 2014
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That thing must post some pretty solid numbers!

Honestly, never was curious till now. Just ran Geekbench 3 64bit. 2791 single core and 31968 multicore, and that's with the stuff still running and pretty stinky (stock 5770) video cards. My guess is that probably nothing too impressive compared to other beefier set ups out there now. But it's a nice machine and I've grown to like it a lot...hard to believe it's 5 years old!
 

ZombiePhysicist

macrumors 68030
Original poster
May 22, 2014
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That thing must post some pretty solid numbers!

So just an update. I ran the geek bench test again and it posted a single score thats basically the same 2777, but the multicore score has gone down a bit to 29890, so a decrease of about 6.5% speed despite the memory working at 1333MHz.

Just an FYI for those seeking absolute max performance, 96GB is probably your max if that 6.5% multicore makes a difference.

I guess I don't understand/know enough about the memory system to understand why there is any slow down at all if all the memory is still working at the max speed, doesn't make sense.
 

ZombiePhysicist

macrumors 68030
Original poster
May 22, 2014
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I recently ran a few benchmarks on my single socket Mac Pro:

https://forums.macrumors.com/threads/1844436/

for a dual socket machine I guess 6 DIMMs will be the best configuration for highest performance.

Agree Mike, 6 slots is peak performance on the dual socket.

Though you had huge drop off in your tests, and in mine, it was only a 6.5% drop to go from 6 slots to 8; it's a pretty mild drop off here. Perhaps in your tests when you used 4 slots the speed didn't stay at 1333MHz (meaning you used 1333MHz memory, but the mac stepped down the speed to 1066MHz) and that accounts for the difference?

Im using the 3.46GHz cpus, I wonder if what chip you use makes a difference too?
 

mikeboss

macrumors 68000
Aug 13, 2009
1,517
790
switzerland
the results posted are for the memory only, not the overall GeekBench scores.

same CPU: 3.46 GHz. I only use 1333 MHz memory modules. you can download the detailed results (HTML files GeekBench), I posted them in the other thread.
 
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