If you're like me and are still waiting for 2019 to roll around with the rumoured release of a new modular Mac Pro, then you might be interested in getting the most out of your current modular Mac Pro by getting more RAM capacity. You might also want to make certain that your current memory configuration is giving you the best possible performance. We show you how!.

Specifications Mac Pros have pretty stringent specification requirements when it comes to memory modules as opposed to a PC based system. The type of memory you need for a Mac Pro is the same type of memory that server class machines use. Specifically, Mac Pros use:. Module type of DDR3 SDRAM. Speed rating of PC3-10600E, 1333 MHz or PC3-8500, 1066 MHz(See below).

Dimensions of 72-bit wide, 240-pin modules. Use a special logic called error-correcting code or ECC for increased stability capabilities.

Mac Pro memory speed will also be contingent upon the type of processor you have installed. For example, if I am running a Nehalem based CPU, the maximum memory speed will be 1066 MHz even if I install 1333 MHz memory.

If I have a Westmere based CPU, I can run memory modules that support 1333 MHz and will run at their rated speed but will also allow for slower 1066 memory modules to be installed and run at the lower rated speed. Buying memory You can get deals on eBay for memory modules of various capacity that can function in your Mac Pro.

However, such purchases can be hit to miss. I bought 32GB of (4 modules) on eBay and when I received them, only 1 of the 4 modules were functional. You can also, find compatible memory on Amazon such as these here. Installing memory The pre 2013 Mac Pros are very friendly to the end user for the ease of access and latch system that the components are installed with.

As such, no tools are required for this operation. Removing memory modules. Shutdown the Mac Pro. Unplug the power connector. Lift the side panel hatch lever. Remove the side panel.

Depress the CPU tray latches. Pull out the CPU tray. Place the tray on a non-static surface. Dress the tabs on each side of a memory module you want to remove. Carefully lift remove the memory module and place it in a static bag for storage.

Depending on your type of Mac Pro, you make have either 4 memory slots or 8 memory slots (single CPU or dual CPU configurations respectively). The process is the same for both except for the number of modules. Do not be so quick to think you need to fill up all fo the memory modules. In fact, the fastest memory configuration will require you to NOT use all of the memory slots. Mac Pros have single, double, and triple channel memory configurations.

This means that depending on where you install the memory modules, the memory can run at its rated speed for a single channel configuration, at effectively double the speed for dual channel configurations, and at effectively triple the speed at triple channel configurations. The Mac can achieve this by 'striping' data to 2 or 3 modules at once for the dual and triple channel setups. If you want a dual channel memory setup, you can fill up all of the slots.

If you want the faster triple channel setup, you can only fill up slots 1,2 and 3 on a single CPU Mac Pro. If you have a dual CPU Mac Pro, the you'll have to fill up slots 1,2 and 3 as well but if you want the best possible speeds you'll also want to fill up channels 5, 6 and 7. The dual CPU Macs Pros will work with only 1, 2 and 3 slots filled but the second CPU will have to share access to the memory channel with the first CPU causing a less than optimal data connection.

Adding memory modules. Line up the pins on the bottom of the memory module with the memory slot. Note that there exists a notch in the module so that the memory can only be inserted in one way. Evenly press the memory module into the slot. Ensure that the tabs on each side of the memory module are 'grabbing' the module and are in the 'closed' position.

Fill the memory slots as per your desired configuration. Re-insert the CPU tray into the Mac Pro. Close the CPU tray latches. Close the side panel and latch. Plug in your Mac Pro. Power up your Mac Pro.

Optimal Memory Configuration For Mac Mac

Final comments If everything went well your newly installed memory should be now accessible. I simply added modules to my configuration to configure it in triple channel mode and my LuxMark results went up 800 points vs a dual channel setup.

If I can eek out that much more performance form my nearly decade old 2009 Mac Pro, then I'm all the happier for it. What about you? Let us know your thoughts on how worthwhile it is to upgrade such old hardware when a new modular Mac Pro coming in about a years time! This post may contain affiliate links. See our for more details.

Hi, I have just upgraded my iMac by adding 16GB (2x8GB) to the pristine 8GB (2x4GB). Since I know, but I may be wrong, that modules should be coupled, how do I have to do it? By now I have made a try, putting physically close, in the 4 available trays, similar modules (4GB with 4GB, 8GB with 8GB). This is the configuration I got from system info (RAM modules coupled in the same bank) BANK0/DIMM0 8GB BANK1/DIMM0 4GB BANK0/DIMM1 8GB BANK1/DIMM1 4GB Is this correct, or should I insert them physically alternated, so they I have the same modules coupled in the same DIMM?

Thanks for your help Francesco. Unless RAM layout changed between the 2015 and the 2017 iMac, I'm pretty sure this is wrong. I just upgraded the memory in my 2017 iMac and tests with Geekbench show that the modules should indeed be paired by DIMM slot, not by bank.

The difference is significant too. With the same modules in different banks I get a memory bandwidth of 30 GB/s, with the modules in the same bank (but different DIMM slots) memory bandwidth drops to 16 GB/s.

Check Memory Configuration

(Which pair of modules goes in which DIMM slot does not seem to make any appreciable difference. I ran the test just once each because numbers were so close. After reading contradictory answers, I decided to make some tests to determine what the correct way to add (2 x 8 GB) RAM to existing (2 x 4 GB) RAM.

And this are the results I found. So I would reseat the modules as I outlined BANK 0 have the same sized modules (x2 2 GB) and BANK 1 the same sized modules (x2 4 GB).

Clearly the person who upgraded your system (it was not Apple) didn't know what they where doing;- Apple never shipped a 12 GB system. The dealer you bought your system from added the RAM. Now one last point!

Don't mix different makes or models of DIMM modules that are the same size! You want what we call a Matched Pair Here you can learn more soon that and RAS & CAS.

Take a look here for more details: Sadly, there is a lot of contradicting information on how the DIMM's need to be installed. So I understand your confusion. As to the layout of what your 2009 iMac had I don't have one to reference so I can't tell you if the physical layout of the DIMM's (using two 2 GB DIMMS) where or were not installed correctly. The marking of the slot should tell you the layout if a Bank was across or one on top of the other.

Its possible the person assembling the iMac messed up. As I mustily maxed out our iMac or Mac Mini's with the same DIMM's I never needed to worry about it as I was always putting in four matching 4 GB DIMM's. Why don't you prove to your self what is the best setup. Since you have a 2009 system with only 4 GB run a timed RAM test with the DIMMS across the banks and within the Bank to see which runs faster.