8GB unstable using OSX Leopard on my MacBook Pro
I bought a MacBook Pro in December 2008 and at the time Apple was saying that 4GB of RAM is the limit on these machines. Then mid 2009 Apple released a revision of the MacBook Pro that supports up to 8GB RAM. Since the architecture of the systems are the same I thought I would purchase a 4GB module and upgrade to 6GB RAM.
This worked perfectly, I got a well needed performance boost on my machine and as I run Windows constantly in VMWare Fusion this helped out a lot.
So being brave I ordered another 4GB module hoping that 8GB should work fine, I installed the module and booted up, so far so good. I looked at system profiler and 8GB of RAM showed up and both module had an OK status. After about 60 secs the machine froze, I rebooted and tried again, same thing. I took the RAM out and made sure it was seated properly and tried again, same thing.
So my conclusion is that OSX Leopard doesn’t support 8GB of RAM on my late 2008 MacBook Pro. I’m eagerly awaiting Snow Leopard and hoping that this addresses the issue if not then I’ve just waste hoping that 8GB should work fine, I installed the modules and booted up, so far so good. I looked at system profiler and 8GB of RAM showed up and both module had an OK status. After about 60 secs the machine froze, I rebooted and tried again, same thing. I took the RAM out and made sure it was seated properly and tried again, same thing.
So my conclusion is that OSX Leopard doesn’t support 8GB of RAM on my late 2008 MacBook Pro. I’m eagerly awaiting Snow Leopard and hoping that this addresses the issue if not then I’ve just wasted 270 pounds. Nice
Did you try booting into 64bit mode, by holding down 6 and 4 at boot? This will force Snow Leopard into 64bit mode.
Then try your two 4GB DIMMS again and reply.
Please specify if it still freezes.
Before anything, confirm under system profiler that you’re in fact running on 32bit mode. Go to about this mac and more info. Then,click Software, and note the “NO” for 64bit Kernel and extensions. Then proceed to the test above
Please let us know
Thanks
JQ
Great post. I am sure a number of people are curious about this. I gave up running VMWare because I found it very slow on 4GB of ram, even with playing with the amount of memory I allow the virtual machine to have. Without being able to run VMWare I have to keep a PC laptop because I need to use PC apps. The price on the 8 GB MacBook Pro is exorbitant.
I’m suprised you found VMWare slow with 4GB RAM, I have run Windows Server 2008 for a long while doing heavy SharePoint development using Visual Studio and various other IDE’s on 4GB RAM allocating 2GB RAM to the VM and found that the performance was more than adequate.
Obviously having 6GB has made things much nicer and 8GB would be fantastic but until VMWare released a 64bit supported version then I’m afraid 6GB is my maximum for now.
I will try this at some point as I’m curious but I have taken my laptop apart too many times now and I can’t be bothered especially now I know it’s pointless as VMWare doesn’t support 64bit kernel mode.
The 8 GiB problem, as well as the lack of K64 in Snow Leopard is due to the firmware/EFI in the 2008 models, but for different reasons. As 8 GiB is supported by the 2008 chipset and CPU, all that is needed is a firmware update, but we both know the chances of Apple ever releasing one. As for x86_64 Snow Leopard, the standard 32 bit kernel has PAE support so that wouldn’t cause a 3 GiB cap like somebody was saying. Anyway, if you really did need K64 for some reason, you are screwed because the 2008 models have 32 bit EFI chips and not the newer 64 bit EFI chips. Although there is a complicated hack in which you can emulate the EFI 64 through Chameleon bootloader (OSX86) using the BIOS emulation on the EFI 32. Of course you are actually going to see a performance hit with that, as well as it being useless for your purposes. (Especially since it has nothing to do with the OS anyway. It is all in the firmware.)
I think your getting confused, my 2008 Macbook Pro supports 64bit kernel mode no problem, the issue is that for some reason it’s unstable running under 32bit kernel mode with 8GB RAM.
I am yet to try 8GB while running under 64bit kernel mode so unsure if that will fix it, however it’s a moo point anyway as my main application VMWare doesn’t support running under 64bit kernel mode.
Sorry, but unless Apple releases a firmware update, 8 GiB of RAM with the 2008 MacBook Pro will not work on any operating system regardless of kernel type. Snow Leopard won’t help. There is no reason you can’t enjoy 6 GiB however. As for VMWare
I can’t say too much because I am bound by a NDA but here is a link you might find really exciting:
http://info.vmware.com/content/6693_FusionTest_REG
Hey I was having the exact same problem but my Macbook is a 2009 version that came with Snow Leopard pre installed on it and I bought 4GB of RAM. I acquired 2 more 4GB sticks and installed them… same results as Lee Dale. I tried the above 64 bit test and had interesting results. the programs worked for a little while but Safari froze and so did the screen and i couldn’t use the mouse to close anything. so I was forced to re-boot. I did so and brought it back up into 64 bit mode and after a few minutes had the same freezing problem but the mouse worked and I was able to force quit the program. After 5 more minutes I had to walk away from my Mac and came back and it wouldn’t restore. I had to press and hold the power button to bring it back up and I got a message that my computer quit unexpectedly. (same message as not running in 64 bit mode)
conclusion… It really sucks! Why doesn’t Apple fix this? When I have talked to them they don’t have any “documentation” that this is a problem…
I had the same issue – 4GB runs like a top, but the minute I put 8GB into my 3,1 MacBook Pro (MBP) things broke. It is sooooooo interesting that it recognized the memory…you would think that if it was such a no-no, why would the OS/BIOS be able to recognize the memory … the O/S would gimp out.