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Cylinder Mac Pro Q&A - Updated May 1, 2017
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How do you upgrade the RAM in the Gray Cylinder Mac Pro models? How much RAM do they actually support?
Please note that this Q&A explains how to upgrade the RAM in the "Late 2013" Gray Cylinder Mac Pro models (MacPro6,1).
EveryMac.com also provides RAM upgrade instructions for earlier Mac Pro models -- the original Mac Pro (MacPro1,1 and MacPro2,1), "Early 2008" (MacPro3,1), "Early 2009" (MacPro4,1), and "Mid-2010/Mid-2012" (MacPro5,1) systems.
Upgrading the RAM in the Gray Cylinder Mac Pro models is a simple process. However, it is important that the memory meet exacting standards to function properly, if at all. Furthermore, there also are differences between official and unofficial details that are important to know, too.
Photo Credit: Apple, Inc. (Cylinder Mac Pro - Back, Left; Cover Removed, Right)
Identification Help
Because the Cylinder Mac Pro clearly is distinctive and these models have been promised to be replaced with an entirely new forthcoming design, you probably don't really need any specific information for identification purposes.
Neverthless, for the purpose of upgrading the RAM, the "Late 2013" Cylinder Mac Pro models can be collectively identified by the A1481 Model Number. They also can be collectively identifed by the
To locate the model identifier, select "About This Mac" under the Apple Menu on the computer, click the "More Info..." button, and click the "System Report" button. Regardless of the number of processor cores, all "Late 2013" Mac Pro models share model identifier MacPro6,1.
The EMC number is located on the bottom of the system toward the outer rim in small type (just to the right of the "Model Number" text). As hand documented by EveryMac.com, the "Late 2013" Mac Pro models share EMC number 2630.
EveryMac.com's Ultimate Mac Lookup feature also can identify these models by their Serial Numbers.
Official RAM Information
Apple specifies that the Cylinder Mac Pro models have four user accessible RAM slots and support as many as four 240-pin "1866 MHz DDR3 ECC SDRAM" modules (PC3-15000).
More precisely, Apple details that RAM for the "Late 2013" Mac Pro models must meet these specifications:
- 1866 MHz DDR3 full length DIMM[s]. Mixing memory speeds is not recommended.
- Error-correcting code (ECC).
- 4 GB, 8 GB, or 16 GB DIMMs.
- Unbuffered (UDIMM) or Registered (RDIMM). Do not mix UDIMMs and RDIMMs.
- 1.5 or 1.35 volts.
- DIMMs with heatsinks are not supported and may damage the DIMM mechanism.
By default, the Cylinder Mac Pro models either ship with 12 GB of RAM (three 4 GB modules and one slot open) or 16 GB of RAM (four 4 GB modules and no slots open).
Unofficial RAM Compatibility & Performance Details
Formally, Apple notes that one should "use the same size memory modules across all slots to maximize performance."
Although four matched memory models is best, in detailed real world testing, site sponsor Other World Computing found that increasing the total memory, regardless of configuration, "will always provide the most significant performance bang for your dollar."
For example, adding one 8 GB module to the three default 4 GB modules in a system initially configured with 12 GB of RAM (for a total of 20 GB of RAM), still is as much as 33% faster than a system configured with four matching 4 GB modules (for a total of 16 GB of RAM). It is worth noting that this 33% performance boost is provided with only 25% more RAM, as well.
However, there also is one critical disclaimer about mixing modules. 4 GB and 8 GB modules are UDIMMs (Unbuffered DIMMs) whereas 16 GB and higher capacity modules are RDIMMs (Registered DIMMs) and these two types of modules cannot be mixed. In other words, you can install any combination of as many as four 4 GB and 8 GB modules, but you cannot install 16 GB or higher capacity modules alongside smaller ones.
You can install fewer than four 16 GB or higher capacity modules. Two 16 GB modules and two empty slots is acceptable, for example. The Cylinder Mac Pro models will not boot if 16 GB or 32 GB RDIMMs and 4 GB or 8 GB UDIMMs are installed at the same time, though.
Actual Maximum RAM
The official maximum RAM capacity in the Cylinder Mac Pro is 64 GB (four 16 GB modules). However, on March 13, 2014, memory manufacturer Transcend was first to announce compatible 32 GB RDIMM modules, making the actual maximum RAM 128 GB.
Although Transcend's press release explicitly stated that the company had "fully tested" these higher density modules and that they "guarantee 100% compatibility," it also was worth noting that the company once before issued a press release trumpeting higher than official RAM capacity and later had to retract it.
However, this time, Transcend's announcement was accurate. On March 26, 2014, after full testing, OWC formally certified a maximum of 128 GB of RAM in the Cylinder Mac Pro with the following note:
While current DRAM device technology limit 32 GB modules to a 1066 MHz memory clock in the Apple Mac Pro 2013, due to enhanced CAS Performance of OWC MaxRAM 32 GB Modules, actual real-world performance is insignificant in low memory need scenarios while offering incredibly significant performance gains in all cases where application use benefits from greater than 64 GB of total memory installed.
In other words, the performance gain of having twice as much RAM more than offsets the performance loss of the slower memory clockspeed.
Apple provides detailed installation instructions, complete with drawings, and these should be reviewed prior to upgrading the memory in your Cylinder Mac Pro.
However, perhaps even better than the official drawings, OWC provides a step-by-step video of the upgrade process:
From watching the above clip, it is readily apparent that upgrading or replacing the RAM in the Cylinder Mac Pro models is straightforward. However, if you do not feel comfortable upgrading the RAM yourself -- or simply do not have the time to do so -- professional installation always is a good choice.
Cylinder Mac Pro RAM Purchase & Professional Installation Options
Just because RAM meets the minimum listed specifications does not mean that it will necessarily function properly, or even at all, in your Mac Pro. Be sure to buy from a quality vendor that has tested their RAM with each Mac model to ensure complete compatibility.
In the US (and many other countries), site sponsor Other World Computing sells memory compatible with the Cylinder Mac Pro as well as all other Macs.
In the UK and Ireland, site sponsor Flexx sells Cylinder Mac Pro compatible memory with free shipping. The company provides flat rate shipping to France, Germany, and Switzerland and inexpensive shipping for all of Europe, too.
In Germany, site sponsor CompuRAM sells quality memory for all Mac Pro models with affordable delivery country-wide and in person pick up and professional installation service available in Munich.
Also see:
- How do you upgrade the processor in the Gray Cylinder Mac Pro models? How is the processor mounted? Which aftermarket processors are compatible?
- How do you upgrade the storage in the Gray Cylinder Mac Pro models? How many drives of what type are supported?
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