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I bought four 1333Mhz DDR3 Ram Moduels to have a total of 32GB of RAM. My Mac Pro is down clocking to 800Mhz. (Mac Pro 5,1. with One 3.2GHx Quad-Core Xeon prcessor.)
Thought this was the exact moduel I needed but still only get 800Mhz in system profiler
Any thoughts from anyone on getting my performance up to at least 1066Mhz?
Thanks Much
Logic Pro, Mac OS X (10.6.8)
Maybe try them one or two at a time to see if one specific DIMM is causing the problem.
Maybe try them one or two at a time to see if one specific DIMM is causing the problem.
Thanks Martin. I'll give it a shot and report results.
Ok I began testing by removing a moduel from slot 4. Booted the computer and two new things happend.
1. For the first time I got a pop up screen telling me the moduels are installed correctlly! See attached.
2. Went the system profiler and Bam! 24GB of RAM @ 1066MHz! After that I did another test by using the moduel I initially removed from slot 4 and put it in slot 3. Again with Three 8GB moduels in, I rebooted and got the same good results with the same pop up. So I feel this proves all moduels are good.
Finally I shut down and installed all Four 8GB moduels and booted up. No pop up telling me the "moduels are installed in the recommended slots." And the system is back to 32 GB but only 800MHz! Booooo!
I believe I read somewhere that having a 4th moduel in place forces the processor to lower the MHz of the moduels to 800MHz? Why is this? What's point of having 4 RAM slots if this is "the way it is'? I there a way around it? If not the biggest question I guess have is....
All things said and done, am I better off with 32GB of RAM @ 800MHz OR 24GB of RAM @1066 MHz?
Please advise...this has made me nuts!
The orginization of the slots is that 1,2, and 3 are independent. 4 shares a channel with 3.
slightly slower results with all four slots populated is not unexpected.
What is unexpected is the downclocking, and by how much.
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You can buy RAM today from a lot of places, under wildly different terms. If it does not work correctly in your Mac, that is not usually an indicator that it is low quality, but that it is not the correct RAM for your Mac.
They cannot 'down clock'. Problem is whoever programmed the module isn't very good at it. The memory is running at 1066 MHz as that is how fast your bus runs. Won't work at all at any other speed.
What is reported in System Profiler is what the modules (incorrectly) report about themselves off the eprom. Hence the statement that they were poorly programmed.
Rick
MacGurus
Thanks so much Grant and Ricks.
I guess this serves me right for trying to up my RAM without severely denting my bank account. You get what you pay for.
So...ignore what the profiler is reporting, the memory is running at 1066MHz, keep all Four 8GB moduels installed to have benefit of 32GB of RAM?
OR should I try and get my money back and order the right moduels for my system? If so, exactly what do I ask/look for beyond what's printed on the moduel sticker in the above picture posted earlier?
STT DDR3 1333 ECC Registered.
Your system doesn't need PC3-10600 although most 1333 MHz modules are programed to also run at 1066 MHz. Some aren't. And to work properly the modules MUST have the correct Apple EPROM.
The memory you have may work ok. No way of knowing without using it and testing it. If you do replace it, just get your memory from a reliable Mac vendor. A high end Mac retailer will give lifetime warranty and will only sell you memory that works in your Mac. PC3-8500 is the proper memory for the Quad Core. No problem with original memory that is 1333 MHz PC3-10600 and sold for your 1066 MHz MacPro, as long as they market it to work properly on the 1066 MHz bus. The memory is the same as long as it is properly programmed.
Rick
Thanks Rick,
Returning the Moduels I bought tomorrow to get money back before the 2 week return expires. I found the 32GB RAM Moduel Kit I really need for yet $100 less than what I paid for the first kit!
The new set:
"fully meets Apple's specifications with special attention to proper thermal specifications."
AND
*About the Apple Specified Thermal Sensor:
Ensuring maximum performance, reliability, and operational feedback –this DDR3 ECC Modules for the Apple Mac Pro 'Nehalem' 4 Core/8-Core and 'Westmere' 6-Core/8-Core processor models feature utilization of Apple qualified components including the inclusion of the Apple qualified Thermal Sensor EEPROM.
You Rick are all that and a bag of chips. Thanks a million!
1333Mhz DDR3 Ram Moduels down clocking to 800Mhz
