Tuesday 29 May 2012

Mac Mini upgrade

My main computer is a mid-2007 Mac Mini. While it's performed very well in the time I've had it, recently I've become frustrated with how slow it is running with Mac OS X Lion.

The cost of a new Mac is beyond what I have to spend at the moment, so I looked into ways to upgrade the Mini. I've previously been hesitant to do this as getting inside the Mini requires some effort. But these are difficult times, so I bit the bullet and opted to upgrade the memory and replace the internal hard disk.

RAM upgrade

I wanted to upgrade the RAM from the 2GB that it came with. This is the maximum that Apple officially support, but you can put more in and it will work. There is a caveat: Due to the chipset used, only 3GB can be addressed by the operating system (even though it will detect more). This meant I could either go for 1GB + 2GB solution, or 2GB + 2GB and effectively waste 1GB of it. I eventually went for the latter because I had read that putting equal sized DIMMs enabled the RAM to run at full speed. I don't know if this is really the case, but the cost difference was very small.

The RAM I bought from Ebuyer was the Crucial 2GB DDR2 667Mhz/PC2-5300 Laptop Memory SODIMM CL5 1.8V (quickfind code: 142421) and cost just over £20 per stick. I bought two sticks.

Disk upgrade

The hard disk that came in the Mac Mini was a 120GB SATA 5400RPM drive. The rotational speed of the disk is at the low end (typical desktops are 7200RPM, with servers having 10000RPM or 15000RPM drives). It was never particularly speedy, but did the job. With the cost of SSDs falling, I could replace the disk with something solid state and much faster.

Ebuyer had an offer on the OCZ 120GB Agility 3 SSD (AGT3-25SAT3-120G) (quickfind code: 268244) costing £80.

There is a lot of discussion about the support for TRIM in Mac OS X. TRIM is a command that the operating system can send to the device to notify it that disk blocks are free and can be wiped. Without TRIM support, disk writes can slow down over time. Official Apple SSDs support TRIM, third party SSDs don't. There is a kernel extension that hacks third party devices, but that was a bit too risky for my liking.

Reading up on the OCZ Agility 3, it includes on-chipset garbage collection that performs  reclamation of blocks in the background. It may not be as good as TRIM, but it does a similar job.
 So, I'm running without TRIM and will see over time how it performs.

Performing the upgrade

Due to the way that the Mac Mini is constructed, getting into the case can be a challenge. You will need a putty knife to get inside the case. Once opened, a very small cross-head screwdriver is required to detach the optical and hard drives. Inserting the RAM is straightforward once this is done. Similarly, replacing the hard disk was pretty easy once inside. There are plenty of guides online that show how to do this.

With the internal drive replaced, there is no operating system to boot from. I had burned a DVD image of the Lion installer and used this to boot the machine (hold down "c" when powering up and until the Apple logo and spinning wheel appears). The DVD has the option to restore a Time Machine backup which I selected. You need to load the Disk Utility to format the SSD, at which point Time Machine can be used to restore a backup (held on an external USB drive) to the internal disk.

The restore process started and I walked away. When I came back, the Mini was asleep and I couldn't get it to wake without performing a power off/on. At which point I didn't know whether it had completed or not. I repeated the process and watched it, moving the mouse every couple of minutes in case power management was sending it to sleep. With six minutes of restore remaining, the machine put itself to sleep. This wasn't power management. This was a crash.

I then tried booting off the original Leopard DVD that came with the machine. I performed the Time Machine restore from here and it completed successfully without incident. I'm not sure if this is a bug in the Lion DVD, but it's worth noting if you have the same problem!

With the machine restored, I booted off the SSD and loaded a few apps. The extra memory and SSD make it feel like a new computer! Where the original configuration was taking up to 2 minutes from power on to the desktop, it now does it in 48 seconds (including Finder opening network drives)! Most applications load very quickly with no noticeable delay.

I previously used Google Mail through a browser as Mail.app felt like unnecessary overhead and was quite slow. Now it's fast and I can keep it open all the time in the background (along with iCal which was another application I had given up on).

Spending £120 on a couple of upgrades has given the Mac Mini a new lease of life. Although the hardware won't be up to running Mountain Lion when it's out later this year, I should be able to get another couple of years out of the Mini, which is definitely worth it.

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