So I got myself a real SSD
It is about half a year ago that I replaced the stock 5.4K RPM drive in my MacBook with a 7K RPM Momentus XT featuring 4 GB solid state cache. Read my post So I got myself a ... SSD-HDD Hybrid about the benefits and drawbacks. Putting my experience down concisely reads like the following:
- The performance gain was big.
- The noise level and in particular the vibrations turned out to be bothersome.
- 4GB cache don't cut it for running virtual machines, and
- I still have a feeling that battery drain was higher.
So, I upgraded again and by replacing the Momentus with a 240 GB Vertex 2. I also replaced the integrated DVD drive with a traditional hard disk to overcome the limitations of 240 GB. I chose a 5.4K drive for reasons of noise and power consumption. It is a 750 GB WD Scorpio Blue. The HD is indeed rather quiet, or even completely silent since it tuns itself off after a while.
The following table lists a few numbers to underline the performance gain of the SSD drive compared to the Momentus XT:
| Momentus XT | Vertex 2 | |
|---|---|---|
| booting virtual windows 7 | 280 | 50 |
| starting and open a solution in visual studio 2010 | 80 | 30 |
| starting R 64 | - | <= 1 |
| starting iphoto | - | 5 |
| maven build and tests | 90 | 59 |
| ruby on rails project rspec tests | 21 | 20 |
| ruby on rails project cucumber (capybara, selenium) tests | 57 | 59 |
The conclusion is clear: ruby tests don't improve with increased disk performance. The JVM builds (there is quite a bit disk access) and test gain 30 per cent. Starting applications is consistently very fast. Virtualization improves very much.
Now, I just hope that the SSD will make it for at least two years. The recent discussions on SSD failure at twitter and in Jeff Atwood's post The Hot/Crazy Solid State Drive Scale leaves some doubt on that.
Update 2011-10-15
SSD works flawlessly
After 5 Month the Vertex2 SSD is still running flawlessly, and I would never return to a traditional drive. On the negative side, I use my private mac-book at work, too. Once you are spoiled by the performance of a SSD, everything else becomes just unacceptable.
I enabled trim support with a hack some while ago. However, according to the system info it is disabled again. I assume that some software update took care of that. At this time I just don't bother, I can't tell the difference anyways.
HDD with issues
Surprisingly, the Scorpio Blue has been more of a trouble maker. The drive spins down into sleep mode as I mentioned above. Unfortunately, the default setting is way too aggressive. When I am working with some file on the drive, the on and off is terribly annoying and very disruptive to my workflow.
I tried several settings with the provided system tools like energy saving and even disabled the sudden motion sensor with pmset. Unfortunately, nothing would work. The only thing that does work is an external tool called hdapm. Apparently, this tool is modifying some bits within the hard-drive. I kept the aggressive spin-down setting as default; i.e. disk1 is set to min in the file /Library/LaunchDaemons/hdapm.plist. Whenever I'll work with the HDD I'll manually issue sudo hdapm disk1 max and after I'm done sudo hdapm disk1 min will silence it down. This is not an ideal situation, but it works for me.