Ram options in the 2013 Mac Pro (R2-D2 model)

[VG3TV]

Is it possible to install 2x4gb and 2x8gb pairs in the four slots available in the new Mac Pro?

If so and there is a performance hit how bad will it be? I can live with a few points of off a benchmark but I don't want spinning beach balls.

 

[cinnamon cider]

I would recommend for you to go to your Apple Store.

 

[Legohouse]

Is it possible to install 2x4gb and 2x8gb pairs in the four slots available in the new Mac Pro?

If so and there is a performance hit how bad will it be? I can live with a few points of off a benchmark but I don't want spinning beach balls.

Memory Upgrade for Mac Pro (Late 2013):

The answer to your question is 'Yes', it is possible to mix different size memory but considering this is a Mac I cannot say it for certain. But make sure other aspects are same. Make sure the speed and the voltage is same. But it is imperative to know if your memory is a Registered ECC (RDIMM) or Unbuffered ECC (UDIMM), as you cannot mix these two types.

Performance-wise, there won't lot of difference if all the memory are of the same speed. If you install lower speed (1333MHz or 1600MHz) with higher speed (1866MHz) then performance will be hit a bit as the higher speed will default run in the same freq as the lower speed memory. Only benchmark can show the actual difference in reality you may not be able to discern it.

Hope that helps.

P.S - I assume this is your model ( http://support.apple.com/kb/HT6054 ; http://support.apple.com/kb/HT6064 )

 

[VG3TV]

That is the model. The support docs don't state anything about mixing sizes and having an issue.
I had a feeling that I would never feel it. I'm going to ask the vendor before purchase again just to make sure.
I knew about the Registered vs Unbuffered issue already. I will have to keep the speed and voltage issue in mind when purchasing the extra sticks though.

Thanks for the info …

Lou

 

[Legohouse]

That is the model. The support docs don't state anything about mixing sizes and having an issue.
I had a feeling that I would never feel it. I'm going to ask the vendor before purchase again just to make sure.
I knew about the Registered vs Unbuffered issue already. I will have to keep the speed and voltage issue in mind when purchasing the extra sticks though.

Thanks for the info …

Lou

Sure, drop us an update on how it turns out. Others might benefit from it.

 

[ywh]

Just received my Mac Pro 2013 and slotted in 2 pieces of Crucial 16GB x 2 RAM (1866). That will theoretically bring it up to 40GB (with the 2 x 4GB stock) but everytime I powered up, there was a loud beep every few seconds and it is definitely a RAM issue.

Took out the stock ram and left the 2 x 16GB alone and the machine flew.

So, it may be safe to say for now (given the lack of info on this) that mixed capacities do not work in the new Mac Pro.

 

[myopicman]

Just received my Mac Pro 2013 and slotted in 2 pieces of Crucial 16GB x 2 RAM (1866). That will theoretically bring it up to 40GB (with the 2 x 4GB stock) but everytime I powered up, there was a loud beep every few seconds and it is definitely a RAM issue.

Took out the stock ram and left the 2 x 16GB alone and the machine flew.

So, it may be safe to say for now (given the lack of info on this) that mixed capacities do not work in the new Mac Pro.

 

[myopicman]

The 16GB and 32GB DIMMs are registered DIMMs, and are known to NOT mix with regular (smaller) Unregistered DIMMs.

Your conclusion that ordinary DIMMs of the SAME type cannot be mixed is not supported by the facts of your experiment.