I recently obtained a 120GB Intel 320 SSD for upgrading my Lenovo Thinkpad X201i from it’s sluggish hard disk to something with a bit sharper performance.
Whilst not the latest and highest performance SSD from Intel, it’s certainly still very quick compared to the hard disk, and it made more sense than buying a more expensive newer model that would be restricted by the SATA 2 bus on my laptop.
The performance increase is impressive, my sequential reads went from 40,300 KB/s to 132,673 KB/s, showing dramatically faster boot performance and snappy application load times. And the seek times jumped massively from 151.4/per second to at least 10,524/per second.
Infact, the SSD is so fast, it can be difficult to get stats of it’s true seek performance. With the seeks completing in only a few microseconds, the bonnie++ tests often finished a bit early and the results would vary, it’s possible the seeks might be even larger than 10k+ per second.
The next major question for me, was what would the performance be if running disk encryption ontop of the SSD. Due to the private nature of my data, I fully encrypt my laptop using dm-crypt/Linux disk encryption with AES 256bit, so that if the machine is ever stolen, the data is unreadable.
Of course, this security imposes an overhead – data needs to be decrypted before it can be read, adding additional overheads, particularly with CPU performance. It’s also worth noting, that the Linux disk encryption implementation is single threaded, meaning that the maximum encryption/decryption performance is limited by the maximum performance of a single core of your processor.
After installing the OS using an encrypted disk, there was a noticeable performance drop. In particular, the sequential reads dropped from 132,673 KB/s to a much less exciting 69,805 KB/s. Whilst still significantly faster than the conventional hard drive’s 40,300 KB/s, it’s a big drop from the true capability of the SSD.
Fortunately the write performance was impacted far less, I suspect because the OS and the CPU core doing the encryption was able to keep up with the slower performance of writing to the SSD, in comparison to the reads. Based on the stats I obtained, it looks like my laptop tops out around 70,000 KB/s, so any additional performance of the SSD above that is wasted.
From a usability point-of-view, even with encryption, the boot time performance is impressive, the laptop starts in about half the time of what it did previously, along with massive improvements in the start time of applications.
The improvements are particularly noticeable when loading a number of applications concurrently – with a conventional hard drive, the need to load data across different physical parts of the disk platters causes a lot of delays when multitasking application loads. On the SSD, I can click a number of applications and have them *all* load within a second or two.
Overall I’m pleased with the upgrade, even with the reduced performance from encryption, the SSD still offers some major performance upgrades and was well worth doing.
The only outstanding downside now is the issue of fitting all my data that I actually want to regularly access on my laptop onto the small size of the SSD…. I’m currently looking into filesystems that provide offline access or caching of networked filesystems from my servers, so that I can have regularly accessed files stored locally, but the full selection just a network transfer away.