Apple released MacBook Pro EFI Firmware Update 1.8 on December 8th, 2009, sparking a new interest in the Late 2008 MacBook Pro models and their maximum memory capacity.
Apple supports up to 4GB of memory in these machines, but OWC has done the testing with our memory modules and has been able to support 6GB of memory since their release. However, there was something interesting we found with our testing when trying to qualify the laptops to accept 8GB of memory. Simply put, while System Profiler recognized that there was indeed 8GB of memory installed, once more than 6GB of memory was actually put to use, the performance of the overall machine diminished.
Of course, when we heard the rumors circulating again that the Firmware Update may have silently addressed this issue as well, we got excited and performed the qualification testing again after installing the update. Unfortunately we found the same scenario on all the machines. The machines were faster the more memory we installed until more than 6GB was present. Once the machine tried to address the final 2GB of memory the performance started to suffer yet again.
It would have been nice to officially support twice the memory that Apple intended, but alas, we’ll have to settle for a 50% increase. Which all in all – isn’t bad.
The machines that were rumored to go to 8GB, are supported to only 4GB by Apple, and have been tested and confirmed by us to 6GB are:
