Chosen Solution
It seems that some people have got 1333Mhz RAMs working on this MacBook. E.g. http://forums.macrumors.com/showthread.p… and http://apple.stackexchange.com/questions… and several more I couldn’t find it now. But many people failed at doing this. And I found a interesting phenomenon. There is two different model of this MacBook. One with Bootrom version MB61.00C8.B02, which is majority, the other with MB61.00C8.B00 which is minority. And it seems that only those with Bootrom version MB61.00C8.B00 can use 1333Mhz RAMs. Can anyone verify this? I have a MB61.00C8.B00 one and recently I’m considering to upgrade its RAMs. I go for as fast as I can, so if 1333Mhz RAMs can be used, and without any side effects. I’ll go for it. Thank you guys!
First I would strongly recommend upgrading your firmware Here’s a link to the Apple TN that explains it all and were to download the newest for your system EFI & SMC firmware updates for Intel-based Macs. As to the needed memory: 256 MB, 512 MB, or 1 GB SDRAM in SO-DIMM’s • 200-pin • PC-5300 DDR2 667 MHz For a max of 4GB per Apple and with the latest EFI third parties have proven 8GB is supportable. Using faster modules 1066MHz or 1333MHz can be used but the bus logic will not run any faster than 667 MHz MacBooks (MacBook Pro’s run at 1066MHz). So why do some systems have problems? This is do to how the memory modules communicate their speed and how the system logic interprets it. In this case the NVIDIA GeForce 9400M also accesses the system memory and the altered speed interfered with it. Heres a bit more on the problem (which also effects MacBooks) Ensuring backward compatibility between DDR3-1333 modules and Macbook Pro There was a firmware bug which broke the override but that has now been fixed. If you do encounter problems there is a utility that you can run to reprogram the memory modules bus speed to comply to the systems needs. The reason this became needed was the older slower memory modules became difficult to get even for Apple ;-} So they needed to make the system able to support the more popular modules. And besides people thought the systems speed would improve with the faster modules (1066MHz & 1333MHz).
I’m currently on this model right now typing with the less released version and can verify that I have it running at 1333 for the RAM. Yes, it even shows that. It’s kind of a moot point though because the bus speed is only at 1066 so the RAM will slow down to 1066 even if it doesn’t show it. There are people out there that will say you can hurt the system by running faster RAM; however, I don’t believe that. Just understand, and you can trust me on this, there will be no performance difference between the 1066 and the 1333 due to the bus speed only being 1066. So why am I running the 1333 if there’s no performance difference? Only due to the fact that this is MacBook I’m selling and have it torn apart currently.
I confirm that the ram (Corsair CMSO8GX3M2A1333C9) on macbook late 2009 MacBook6,1 MC207LL / A system that has the 2.26 GHz P7550 and the MB61.00C8.B00 boot ROM today with 2x4GB 1333MHz works perfectly sees the 8GB and runs at 1333MHz . Good upgrade to all of you. Update (10/07/2017) These are the photos as a demonstration for those who might have doubts about when done.
Hi, I have some interesting info. My MacBook late 2009 has bootrom MB61.00C8.B00 and I was UNABLE TO address more than 6 Gb (strangely enough 1 x 2 Gb 1066 + 1 x 4 Gb 1333). I work in a components store, so was able to try all kinds of modules (with differences in latency and clock speed). In other words, 8 Gb with my Mac turned out to be an impossibility. Then I had some issues with the Mac and I brought it to an Apple store for repair. They replaced the logic board. I still have bootrom MB61.00C8.B00, but now I CAN address 2 x 4 Gb (1066 as well as 1333 modules, while 1066 is seen by the system as 1066 and 1333 as - you guessed right - 1333 Mhz). Don’t ask me why or how. Cheers, KNOKKi P.S. I used the same modules which formerly did not work, so differences in modules can be ruled out as a cause.
Hi Xinan, I have the same exact computer and the same exact query! Can you confirm that your machine is now working on 8GB RAM? Are the chips 1066MHz or 1033? Thanks man :) Raj
Hello. I have MacBook Late 2009 White unibody, with the bottom *B00 mentioned above and I am currently running 2x2GB 1333 MHz modules in it. No hassle.
I upgraded my MacBook6,1 MC207LL/A system which has the 2.26 GHz P7550 and the MB61.00C8.B00 boot ROM today with 2x4GB 1333MHz (Corsair CMSO8GX3M2A1333C9) and it is indicating the RAM is 1333 MHz and I haven’t encountered any issues yet. Update: Although the system was stable, it did seem to be running quite hot. I didn’t spend enough time using it before upgrading the RAM to know if this was due to the RAM or not. I went ahead anyway and underclocked the RAM to 1066 MHz by modifying the SPD of one of the sticks using i2cdump and i2cset in an Ubuntu install on a USB stick.
