DDR2 667 shows up as DDR2 800 for some reason,,

Question

Hi all,
My "problem" is the following..
I just bought myself 2 new Kingston 2GB DDR2 667 memory modules. Thus expanding the memory of my macbook to 4GB's of ddr2 667. Now when i enter the system specs @ " About this mac" the system tells me i am actualy running 4Gb's of DDR2 800 mhz memory..
I thought the white MB881M/n macbook didnt support 800mhz memory..
Now my question is:
Would it be wise to buy 800mhz ddr2 and use THAT in stead of using the 667mhz memory wich the machine is obviously overclocking.
And IF the machine is actualy overclocking the current memory, could it be harmfull? Will it actualy be faster at 800 then at 667? Is the machine actualy overclocking the memory, or is it just a bug in the system showing 800mhz in stead of 667?
I thought the macbook i have couldnt support 800mhz but if for some reason it can i think it would be "wise" to put the "real deal" 800mhz in it..
Cheers
Message was edited by: Jarno Hofman

Answer 1

Kappy wrote:
Well, OS X has no built-in capability to overclock RAM. Doing so requires overclocking the bus and that would require special software (I don't think any such software exists for Intel Macs.)
The documentation I have even on the Early 2009 White Macbook specifies DDR2-667 MHz RAM. I don't know why System Profiler is reporting 800 MHz.
Here's my (multi-part) theory, and it's from thinking about all the reports we've been hearing about older generation MacBooks and the newer white MacBooks.
People have been reporting that the lastest (early 2009) white MacBook does actually use PC2-6400/DDR2 800 memory and runs it at native speed. It's not actually "overclocking" anything; it's actually capable of it even if not documented by Apple. It's using the same NVIDIA chipset as the Unibody MacBooks, and they're capable of using PC3-8500/DDR3 1066, so it's not a stretch to believe that they're capable of using DDR2 800. Intel's latest chipsets are capable of using DDR2 or DDR3 modules, but the type is going to be limited to the physical socket type.
All reports are that correctly labelled PC2-6400/DDR2 800 memory doesn't work properly in any of the earlier MacBooks that specify PC2-5300/DDR2 667 except in cases where it's mixed with one slower speed module. One would think that the SPD should contain secondary settings, but that doesn't seem to help it work unless there's another slower speed module that forces the memory controller in the chipset to operate both at the same speed.
A few people who have purchased Kingston (especially the KVR "ValueRAM Series") DDR2 667 modules have reported similar incompatibility as with clearly labeled
DDR2 800 modules. Here's one report:
http://discussions.apple.com/message.jspa?messageID=9507719
My final theory is that these modules are sold by Kingston as DDR2 667 but are in fact DDR2 800 modules. This would A) cause the older MacBooks to not recognize it alone and B) cause the newer MacBooks to run it at a faster native speed.