Upgrade the memory in select 2009-2010 Mac Pro systems or compatible PCs using the 16GB DDR3 1066 MHz UDIMM Memory Kit from OWC / Other World Computing. This memory kit features a total capacity of 16GB, which is made up of two 8GB modules. It features a clock speed of 1066 MHz, a bus speed of PC-8500, and a 240-pin UDIMM form factor. It operates using 1.5V, 7-7-7-20 timings, a component configuration of 1024M x 72, and a module bandwidth of 8.5 GB/s. By offering ECC (Error Checking and Correcting) technology, this RAM will help your workstation encounter fewer errors that can corrupt data sets and introduce system issues. Additionally, this memory module is compatible with Apple Specified Thermal Sensor, which ensures that the RAM maintains a safe thermal operating range.

16GB (2 x 8GB) Capacity    1066 MHz Clock Speed    PC-8500    240-pin UDIMM    1.5V    7-7-7-20 Timings    ECC    Apple Thermal Sensor Compatible    Module Bandwidth: 8.5 GB/s    Compatible with the Select Mac Pros

Model ID: MacPro4,1

Quad-Core: 2.66 GHz, 2.93 GHz, 3.33 GHz

Eight-Core: 2.26 GHz, 2.66 GHz, 2.93 GHz

Model ID: MacPro5,1

Quad-Core: 2.8 GHz, 3.2 GHz, 3.33 GHz

Eight-Core: 2.4 GHz

Model ID: Xserve3,1

Quad-Core: 2.26 GHz

Eight-Core: 2.26 GHz, 2.66 GHz, 2.93 GHz

Compatible with Intel / AMD-based PCs capable with the specifications listed above. Memory complies with JEDEC Specifications, document JESD79-3B

Related Questions and Answers

Q: 1. Will this 64Gb RAM upgrade speed up a 2013 Mac Pro (currently with 32Gb RAM) running heavy video / 4K content and applications?

A: That depends. Are you running out of memory? If you still have 50% of memory available while you are running the app then you probably won't notice a difference. It might be possible you need a processor upgrade instead. Find out why it is running slow first, then upgrade the correct part. But, yes this will give you 32GB more RAM if you install the upgrade, and theoretically improve performance.

Q: 2. I have a RAM with error among 4x32GB. Can I replace just one?

A: They should be replaced in pairs.

Q: 3. There seems to be some doubt whether or not the 64GB (4 X 16 GB) would be readable by a iMac 5K 27 Late '13 model, but upgraded to current operating standards. From what I've read so far, it looks like it will only read up to 32GB of memory. Will it see all 64 or just utilize the 32GB that it says it can be upgraded to? Much confusion here! Don't want to make a $829 mistake here...

A: I'm sorry, but the 2013 iMac tops out at 32GB's of RAM.

Q: 4. Can this be used on an imac 5K 2016?

A: Sorry, no. This memory is for the 2013 Mac Pro.

Q: 5. Is this compatible with iMac (Retina 5K, 27-inch, 2017)?

A: Yes, it's working perfectly fine in my iMac retina (2017) 27 inch model. I added in 64 GB from two of these kits. Easily slid into the RAM slots

Q: 6. is this overclockable to 2133 or 2100mhz ?

A: The manufacturer has not published any information about overclock potential other than the following: XMP 1.3 support for automatic overclocking

Q: 7. Is this item Compatible with 27-inch iMac (mid 2017)?

A: Yes, this would be the correct RAM to use on an iMac 27" from mid 2017.

Q: 8. Can I use those OWC in addition to my Mac Pros (12 core mid 2012) original Hynix modules?

A: I can tell you that those dimm work fine in your mac, but I don' t know if you can mix with others . In fact I had incompatibility problems with other dimm ( not The original).

Q: 9. My 27" late 2015 Mac OS has room for two 8GB memory modules. Cheaper to buy one 16GB. Can I use one 16GB instead of 2 8GB?

A: Yes you can. The system works best when its in pairs, so if you plan on adding another card it should be a 16GB not a smaller or larger size.

Q: 10. is this compatible with the newest Intel i9 3.6GHz iMac 27" (2019)?

A: This ram is not compatible with the latest iMac (Early 2019) model. The compatible ram will be BH #OW2666D4S32P.