Mac Mini Memory (Part 1)

I’ve been using a Mac Mini (2.0GHz Core 2 Duo/1GB memory) for iPhone development. Mostly, it’s great, but it is a little low on memory. It always seems to have enough to run whatever I’m using at the moment w/o any problems, but switches between programs (Xcode->Interface Builder->Safari) generally involve some delay as pages are pulled off the disk. I decided to do a 4GB upgrade. It didn’t go very well; here’s what I learned along the way.

Resources

Upgrading a Mac Mini’s memory is a little intimidating; first of all, the case is clearly designed to be hard to open, and the internals are unlabeled, delicate, and tightly-packed. Fortunately, there are some good guides to the process. I quite like these two:

• Video: How to open a Mac Mini
• Tutorial: How to replace a Mac Mini’s memory

What They Don’t Tell You

Unfortunately, all the guides I’ve seen leave out certain crucial pieces of information. The three biggest lacunae are:

• The size and type of the putty knife you use to open the Mac Mini matters – a lot. I found that a 4″ knife works pretty well. 6″ is too big to fit inside the case and 1.5″ is too small to push enough of the retaining clips at one time. I think a 5″ knife would be just about perfect, if you could find one. Some guides recommend that you use a plastic knife to avoid scratches; this seems fantastic to me, as the knife must been very thin to fit inside the case, so metal seems to be the only option.
• Every generation of Mac Mini is wired a little differently inside the case. For instance, the tutorial I linked above indicates that there is a wire under the optical drive and next to the battery that needs to be unplugged. There is, on the generation that the tutorial was written for (1.83GHz Core 2 Duo). On my (only slightly later) machine, however, this wire has been deleted from the design. When doing an upgrade, find a guide tailored as closely as possible to your specific model.
• Mac Minis can be incredibly picky about memory.

Failure!

After getting my case open, and working my way down to the SO-DIMM slots, I performed the upgrade. I replaced the factory 1GB module with 2x 2GB modules – specifically, a pair of Patriot PSD34G1066SK modules I bought from Fry’s Electronics. I powered the computer up, and things looked great; the machine showed 4GB installed, I was able to run Xcode, Interface Builder, the iPhone Simulator, iTunes, and some big pages in Safari, and switch between them fluidly. I closed the case up, and got back to work.

Just to be sure that things were working ok, I kept a lot of applications open while resuming my work. Within 10 minutes, my computer crashed. The symptoms included a badly garbled display, and corrupted audio output. Naturally, the machine was unresponsive to KB input, so I powered it down by holding the power switch for ~10s.

The machine refused to reboot.

I reopened the case, and replaced the original memory. This appears to have restored the system to proper operation. Although the system is no faster than it was before (and there are even some extra scratches on the inside of the aluminum housing) I now appreciate its smooth operation a lot more. So I suppose the upgrade did make me happier, in a way.

Future Steps

I will try the upgrade again, with Apple-approved memory – possibly by having an Apple tech do it. (For the brief time it worked, the 4GB experience was a definite improvement.) I’ll post a followup when I have some news.

Incidentally, if you Google around for problems with this upgrade, you’ll find a lot of reports of this sort of thing – proof of the importance of knowing what to look for, I suppose. Some people suggest attempting to reseat the memory when this happens. For the record, I didn’t bother with that step, as lots of people reported that it didn’t help, and I didn’t see anyone say that it definitively resolved their problems.