Flash-based solid-state drives with more than 64 or 128 GB of capacity are fairly small, but they're still really expensive relative to hard drives. Compressing the Windows partition frees up some space, but is that really a good idea?

As enthusiasts, we're forced to contend with a number of obstacles in our quest to continually keep performance balanced without overspending. New processors, graphics cards, memory kits, power deliver, and storage performance are all potential bottlenecks along the way. Fortunately, capacity isn't as big of an issue. Even 2.5” hard drives offer capacities of more than 750 GB, which is more than enough for most folks. Despite Microsoft's best efforts to continue inflating the size of a Windows installation, you're still left with plenty of room for music, movies, games, and photos. Of course, there's always the option to use 3.5" drives, which currently hold multiple terabytes each. Talk about shattering capacity barriers.

Depending on the model and manufacturer, you could have found 2 TB drives for as little as $80 before the recent flooding in Thailand, which had a severe impact on the supply of conventional hard drives. Filling such a large repository might sound unfathomable to mainstream folks, though anyone with an extensive movie collection could manage it in fairly short order. Be that as it may, storage space is typically not an issue today for folks with big hard drives in their machines.

The situation is quite different for adopters of solid-state technology, though. These drives are just as easy to fill with data. But, compared to mechanical hard drives, they offer a lot less capacity, making each available gigabyte count for that much more. In fact, each gigabyte is quite literally more valuable, since you often have to pay more than $2/GB of solid-state storage, where hard drives are priced in the pennies per gigabyte range.

Small SSDs equipped with less than 60 GB reach their limits almost immediately just by installing Windows, an office productivity suite, and importing email. The lack of capacity is further exacerbated by the fact that wear leveling algorithms don’t work efficiently when the drives are completely filled. That's why we often recommend using an SSD for performance-sensitive information and hard drives for user data.

We already examined methods for recovering free space from an SSD in a separate article, so today we're focusing on the pros and cons of another approach that Windows offers right out of its box: the NTFS file system's data compression feature. Once you enable it, no further action is required, making it pretty convenient. But are there other caveats to bear in mind?

Our test lab addresses the pressing questions: how do you enable data compression, what is compressed, how much capacity can be gained on a typical Windows installation, and how much does this feature affect the performance of the SSD?