Pity OS X doesn’t like 8GB of memory in my MacBook Pro
I received a flurry of questions via email when I posted information the other day that I had 8GB of memory in my Apple MacBook Pro. At the time of my post, I had only intended to boot the OS and see that it appeared to work correctly, recognize the updated amount of memory and shutdown cleanly. In other words, a short cursory test.
But the questions kept coming so I decided last night to reinstall the memory and do more testing. This time I decided to put my ThinkPad T61p back to it’s original configuration of 4GB RAM and do some longer term testing on the MacBook Pro.
Now For The Bad News
Unfortunately after running the MacBook Pro for almost 24 hours, it isn’t looking good. One of the key scenarios for wanting to move to 8GB isn’t working worth a damn. I’m talking about virtualization.
VMWare Fusion Testing
I started my virtualization testing using VMWare Fusion. It’s my preferred Mac desktop virtualization product and considering I purchased it last October, it seemed to be the logical place to start. I already had several virtual machines built and waiting in the wings for testing. To be specific, I tested Windows Vista Enterprise SP1 x86, Windows Server 2008 Enterprise x64 and Red Hat Linux Desktop 5.1 x86.
The very first test I ran was to increase the memory allocation on the Windows Vista virtual machine from 1GB to 3GB. Seemed like a simple enough test. I mean after all, if that ran well, then it would be time to run Windows Server 2008 with a similar memory allocation, thus proving Fusion and OS X could handle the memory above the 4GB 32bit line. Bad idea. Booting the VM with 3GB of memory slowed the entire system down. I mean really slow. Firefox and Entourage were almost unusable to the point that they wouldn’t respond to mouse clicks.
When I booted up the Windows Server 2008 virtual machine, the overall system performance ground nearly to a halt. That’s not good. The Windows Vista VM was set to 3GB and the Windows Server 2008 VM was set to 2GB. Clearly something was wrong. At the suggestion of one of our internal Mac enthusiast, I removed VMWare Fusion 1.1.3 and installed VMWare Fusion 2 Beta 1. No change in the results. So I’m thinking at this point there are still a number of variables to consider and we don’t yet know who the real culprit of the problem performance is. How do we remove a variable?
Parallels Desktop for the Mac
In order to remove one of the variables, the simplest solution seemed to be removing VMWare Fusion and installing and testing Parallels Desktop for the Mac 3.0. If by a stroke of luck Parallels worked flawlessly, then we would at least know there’s a bug in Fusion and it needs to be reported to the VMWare team.
Unfortunately it doesn’t look like Parallels is going to fair any better than Fusion. The maximum amount of memory you can allocate to a Windows Vista virtual machine is 2GB. I didn’t look to see if there was a hack to allow for more. I created a Windows Vista Ultimate x86 VM and allocated 2GB of memory. The install was fairly painless and execution of the VM after installing the Parallels Tools was pretty good. The overall OS X and system performance was no where near as bad as the Fusion experience.
But that was only one 2GB virtual machine and we need more. So I decided to create a Windows XP Pro x86 virtual machine. So far it’s been installing for about five hours. Now keep in mind nothing else is running on the system other than Parallels and this install. The Windows Vista virtual machine isn’t fired up and running yet. This isn’t looking good.
So where does this leave us?
Good question. I don’t have a good answer yet. When the XP install finishes, I’ll certainly run it and Windows Vista to see if they’ll behave and work correctly. If they don’t, the next thing I’ll do is pull the 8GB of RAM back out of the machine and reinstall the 4GB of memory to see if the virtual machines work properly (with smaller memory allocations). I don’t see much point in testing a 6GB configuration by mixing a 2GB SoDIMM with a 4GB SoDIMM. That is unlikely to solve the performance problem although it is probably an interesting configuration choice for a few of you.
Assuming by pulling the memory out of the box, things settle down and perform properly, then Apple, VMWare, Parallels and Kingston have some work to do. At that point it would not be apparent if the 4GB sticks are in fact faulty, or OS X needs a fix, or Fusion and/or Parallels need a fix. This would certainly be out of my hands for any further testing.
I’ll update this post tomorrow and as needed over the next few days to give you updates on my observations but I wanted to let you know things aren’t looking good at the moment. On the bright side, the 4GB sticks have performed absolutely flawlessly in my Lenovo ThinkPad T61p with Windows Vista Enterprise and Ultimate x64, Virtual PC 2007 SP1 x64, Virtual Server 2005 R2 SP1 x64, Windows Server 2008 Enterprise x64 and Hyper-V, and a whole boatload of applications.
It’s a shame I can’t say the same for the Mac. Hopefully Apple will come out with a “certified” sku or configuration soon. I have already informed Kingston and have requested an Apple SME if they have one.
[UPDATE for 7/10] As expected, Parallels ran slightly better but took a nose dive off the cliff when I started two virtual machines. I pulled the two 4GB sticks out and reinserted the two original 2GB sticks from Apple and everything ran MUCH better. At this point it looks like there is some sort of compatibility issue. I’ll let the makers of the products figure it out. Sorry, until they do you are better off running a good Windows machine with an x64 version of our OS if you need more than 4GB of memory. Sad but true. I tried.
[UPDATE for 7/11] I configured my Mac for bootcamp and installed Windows Vista Enterprise x64. I also installed Windows Server 2005 R2 SP1 x64 and ran three virtual machines with the 4GB of system memory configuration. No issues. That ran well. I shut things down gracefully and installed the two Kingston 4GB sticks bring the total system memory up to 8GB. The machine would barely boot Windows Vista and run. It is now apparent to me the memory sticks I have have some sort of incompatibility with the MacBook Pro I have. My testing of this has now concluded. It’s up to Kingston and Apple to resolve.
