I have an early 2009 mac pro, with eight core 2,26ghz. Installed memory are 6x 1gb DDR3 PC3-8500 (1066mhz). Can i add or replace them with 2x 16gb DDR3 PC3-12800 spec? Thanks.
Mac Pro, macOS High Sierra (10.13.3), Early 2009 Eight core 2,26ghz
In the 2009 Mac Pro, running one click higher (1333) DIMMs seems to work for DIMMs from MOST vendors. It will gearshift and work at the slower speeds -- so do not pay extra, you cannot use the speed increase with your quad processor(s)!
I recommend you shop extremely carefully, and get DIMMs with a return policy. Otherwise, you risk owning DIMMs that are perfectly good, but don't happen to work in your Mac.
Also, ALL DIMMs over 16GB are registered DIMMs, and will not play nice with UnRegistered DIMMs.
When your new ones arrive, remove ALL and test the new ones alone in your Mac. Then you have all "Known-good" DIMMs, and the problems (if any) will be easier to debug.
--------
NB> Faster-rated DIMMs are Notorious for NOT working (but being flaky instead) in MacBooks -- use only the exact spec DIMMs in a MacBook!
Wow what a useful article you got there :) thanks for sharing, will read them carefully.
The problem for me, to get those PC3-8500 is quite hard (also tend to be more expensive as its old tech), while PC3-12800/10600 are easier to get with only a bit of price difference.
Thanks for your advice. I am using it on a Mac Pro, been reading from somewhere, telling me that using higher bus speed should be okay. Yes the speed will goes down, but it will works just fine. Still i found no article or result on combining those PC3-8500 with 12800/10600.
I am trying to put 2x 16gb (12800) + 6x 1gb (8500) :) but affraid of something bad happened to the machine.
Go to Crucial.com or OWC Macsales. Either company are reliable and give you a lifetime guarantee.As I don't know which country you are from - Google the names and a suitable link will arise. I know budgets can be important but both these people are well regarded for both price and quality. And they have a personal one to one telephone link in most major countries.
I am trying to put 2x 16gb + 6x 1gb 🙂 but affraid of something bad for doing so.
NO. You can NOT do that.
16GB DIMMs are Registered DIMMs. Those modules have so many chips on the DIMM that they need an output Driver Register to work at all. This Register electronically overwhelms the puny outputs on Unregistered DIMMs, and makes it impossible for the Unregistered DIMMs to work.
If you install ANY Registered DIMMs, you will need to set aside ALL Unregistered DIMMs -- they do not work together in the same machine.
You do so at your own risk. You should only use matching RAM in Apple machines.
This document may be a useful good guide.
https://www.lifewire.com/2009-2012-mac-pro-memory-upgrades-2260368
Use 12800 ram instead of 8500?
