Yes, it will downclock.It'll definitely down-clock faster RAM as the limitation is with the FSB (I think?).
For older Intel based MP systems, only FB-DIMM's could be used. But this changed with the Nehalem and Westmere based processors.I didn't think it would even recognize non-ECC RAM
I actually have a 2008 MacPro, I was just curious as I read on an audio computer forum of a system builder that pulls out the Apple Ram and uses non-ecc 1600 MHz RAM, I'm guessing he buys the computers from apple with the minimum 4gb RAM and installs the recommended 6gb for 4core machinesIt'll definitely down-clock faster RAM as the limitation is with the FSB (I think?). This has no bearing on whether you're using ECC RAM or not. Are you running with a Xeon? I didn't think it would even recognize non-ECC RAM
Ah right, no FSB. Is the max memory controller frequency a characteristic of the logic board? Its not a direct limitation of the CPU, correct? Such a shame that Apple would restrict something like that. I guess I shouldn't be surprised thoughYes, it will downclock.
It's not FSB though, as it's a different architecture (FSB was eliminated in favor of an on-die memory controller and the Quick Path Interconnect to communicate to the chipset). But it is due to the max memory controller frequency (spec set by Intel; not all parts can run at 1333MHz either).
Though on 2009 systems, the firmware is the restriction as Apple fixed it to 1066MHz. So even if the memory controller is actually capable of running 1333MHz (W3570 or W3580 equiped systems for example) and 1333MHz memory is installed, it only runs at 1066MHz (confirmed via testing by MR members).
Thanks for clearing this up. I had certainly mixed up information from different places.For older Intel based MP systems, only FB-DIMM's could be used. But this changed with the Nehalem and Westmere based processors.
The i7 parts using the LGA1366 socket have the same memory controller as the SP Xeons with ECC disabled. So the Xeon variants can run non-ECC memory, but it must all be non-ECC (you cannot mix memory types; same goes for UDIMM and RDIMM - one or the other, never mixed).
In the case of the 2009's, the limitation is due to the firmware, so that could be considered a board limitation (though this could have been addressed via a firmware update). Assuming 1066 or faster RAM is installed of course.Is the max memory controller frequency a characteristic of the logic board?
I'd need to get the details as to what has/hasn't worked, but it's some detail in the specs (i.e. timings are a bit different; gaming memory, such as the Mushkin Silverline is, has a tendency to be hit or miss from what I've seen/heard).newer MPs can use non-ECC, but not every one will work. I'm not sure what the requirement is, but it has nothing to do with a thermal sensor. I've tried Mushkin Silverline RAM, and my MP didn't even boot, and now I'm using Crucial.
also, I bought my computer used, and it came with a mix of ECC and non-ECC...worked perfectly fine. I switched it all to non-ECC when I added more RAM, though.