If you're tempted to buy a PCI Express-based SSD and add your own conventional storage, OCZ's RevoDrive Hybrid could might suit you. A 120 GB SSD and 1 TB of disk space come together on a four-lane PCIe card to serve up an advanced caching solution.

Enthusiasts shopping for storage face a gut-wrenching decision. Do you buy a hard drive and enjoy gobs of capacity for a very low cost, accepting that it'll be relatively slow. Or do you scoop up an SSD, pay significantly more per gigabyte, and get a lot less capacity? 

When you do the math, it's easy to figure out what the extra performance of an SSD costs you. For $80 you can either purchase a 2 TB hard drive or a low-end 60 GB SSD. That comes out to $0.04 per GB for the hard drive and $1.31 for the SSD (and oh, by the way, the cost per gigabyte on the SSD only goes up from there).

So, do you pick capacity or performance?

How about splitting your budget in half and spending money on a smaller SSD and hard drive, in the interest of enjoying the benefits of both? The challenge there, at least for some folks, is actively managing the applications that live on the SSD and balancing that with conventional storage space.

OCZ is trying to offer a more streamlined option with its RevoDrive Hybrid by matching a 1 TB hard drive up to a 120 GB RevoDrive 3 for caching. This combination is supposed to deliver solid-state-class performance at a fraction of the cost you'd pay for a 1 TB SSD. 

While the $500 asking price certainly feels more SSD-ish than characteristic of a hard drive, the math indicates $0.50 per GB. That's far less than the $1.75 per GB typical of leading SSDs like the Vertex 3.

Our experience with SSD caching solutions has been mixed. The Smart Response Technology component of Intel's Z68 Express chipset is great in that it's built into the core logic and only really requires a $120 SLC-based SSD 311 to enable it. But, practically, the performance improvements are largely situational, and certainly not what you'd hope for from an SSD. Add-in solutions like HighPoint's RocketHybrid aren't much different. To that end, we're still recommending that enthusiasts who want the experience of an SSD go the mixed-device route.

However, that's the conclusion we've reached based on the caching devices made available to us so far. Often, they're either handicapped by a small SSD or a slow drive. OCZ is the first company to come out with something different: a blend of solid-state and magnetic storage in one package. The promise, at least on paper, is that we'll see the speed of a RevoDrive 3 without sacrificing the space typical of a hard drive.