Solid state drives (SSDs) have been growing in popularity over the past few years. With their small size and lack of moving parts, the benefits are clear; they’re fast and resistant to physical damage.

So why are hard disk drives (HDDs) still in use? The put it simply, cost. The cost per gigabyte of storage is a lot higher for solid state drives compared to hard disk drives – a 1TB hard drive is about one tenths the equivalent of solid state drive storage. But in 2010, some hard drive manufacturers came up with a third way – the hybrid drive. Designed to bridge the gap between HDDs and SSDs, they marry the speed of SSDs with the cost-effectiveness of HDDs.

Solid state hybrid drives (SSHDs) combine cache with platters found in traditional HDDs. They are normally comprised of a small capacity of flash storage – typically 16 or 32GB – with a larger capacity HDD. The theory is that “hot data” - that which needs to be accessed frequently – can be cached on the SSD and retrieved quickly. You can actually do this manually by installing an SSD to your machine, but solid state hybrid drives have this optimisation built into the firmware, removing the need for manual moving of files.

Despite the advantages – notably enhanced performance coupled with a high storage capacity – SSHDs are by no means perfect. They lack the durability and silence of SSDs, since they still utilise electromagnetic platters. In the end, though, these hybrid drives are a happy medium between hard disk drives and solid state drives, at least until the cost per gigabyte of flash storage comes down.