MacPro 6.1 memory in 5.1

The number of pins, voltage and DDR3 designation looks to be compatible.

There are lots of sad stories here on the forums about folks who bought RAM that appeared to be different from their original RAM in ONLY that the clock speed was faster. They plugged it into their Mac, and ...

... discovered it did not work, because it could not shift down properly to run at the slower speed. Now they own some very fine modules that work great -- but do not happen to work in their Mac.

Once you get close to 8GB modules, you run the risk of encountering different chip organization and registered vs. unregistered problems.

If you had some modules that "fell on you", you could certainly try them. But pay money for stuff that was not sure to work, and is generally not returnable easily? That is not to my liking.

No. The memory for the MP 6.1 (late 2013) is not compatible with earlier MPs

It's work.

I have mac pro 6.1,and i upgraded its memory.

I put memory from mac pro 6.1 into 5.1,It's working compatibly.

Check that processor on Intel Ark page for what memory it can support, if it is 56xx series I would give it more of a chance if the firmware code of the DIMMs and SMC can talk to each other. It is up to the processor in large part and the processor daughter tray I would think.

I think, I have read, of people (trying) to use even 1600MHz instead of 1333MHz DDR3 in a cMP.

So in lllaass' case, it seems his father Mac Pro late 2013 memory DOES step down and run properly at the lower speed of the 2009 Mac Pro.

Otherwise, the Error Correction Hardware would be going crazy.

MacRumors, someone had some memory from their 6,1 after an upgrade, threw it into 5,1 and is working - so OEM Apple 1866 DIMMs

some folks on eBay have no idea what they are selling.

Others are remarkably clever.

If you watch intently, sooner or later someone will say "I also tried these in my silver tower Mac pro 2009-2012, and they work great". Money back guarantee.

>> Buy those!

Could you post more of a description of the DIMM that worked?

like who made the chips, how many RAM chips (the ones that are all the same), chips on one side or two, what is its size in GB, and if there is a maker of the DIMM itself?

Thanks!

The hatter

There are a lot of different DIMMs of different sizes with different chips organized in different ways that are all "Apple OEM". Some work, and maybe some do not. I think it is too much of a stretch to say with certainty, "all Apple OEM work".

That is why I am fishing for more information about exactly which modules these were.

Wasn't trying to be covering every eventuality and comprehensive of every if-then-else, but I'll bet memory is fully downward/backward compatible, even with just a couple reports.

Same for server pulls of 667MHz FB-DIMMs are found to be dirt cheap and work and work in 2006-8 too.

Frequently higher speed memory will not work. Try at your own risk

Yours was the first one post I have seen on that subject.