The value perspective
Welcome to our famous value analysis, which adds capacity and pricing to the performance data we've explored over the preceding pages. We used Newegg prices to even the playing field, and we didn't take mail-in rebates into account when performing our calculations.
Our remaining value calculations use a single performance score that we've derived by comparing how each drive stacks up against a common baseline provided by the Momentus 5400.4, a 2.5" notebook drive with a painfully slow 5,400-RPM spindle speed. This index uses a subset of our performance data described on this page of an earlier SSD round-up. Some of the drives were actually slower than our baseline in a couple of the included tests, so we've fudged the numbers a little to prevent those results from messing up the overall picture.
Since the RAID configs couldn't participate in DriveBench, a major component of our overall performance score, they'll be forced to the sidelines for our value analysis. You're not missing much. If we take all the DriveBench results out of our overall score, the picture looks like so:
Not pretty. Only the Force GT gets an overall boost out of RAID; doubling down on the other budget SSDs actually results in lower overall scores.
The solid-state arrays look worse here than they have in most of our individual tests thanks to FileBench. We use FileBench's used-state copy times in our overall score because we think they represent long-term performance better than factory fresh results. Without TRIM support, the RAID arrays offer painfully slow used-state copy times, dragging down their overall scores.
We're not inclined to completely revamp how we calculate our overall performance index just because RAID arrays can't deal with TRIM, which is sort of a big deal. Instead, we'll drop the RAID results to focus on the overall performance of our single-drive configs, DriveBench included.
Our overall score confirms the notion that size indeed matters when it comes to SSD performance. We knew as much from the manufacturer spec sheets, but it's interesting to see how the different drive families and capacities compare across a wide range of tests.
The Force 3 has the most even gaps between the capacity points we tested. The Force GT and Crucial m4 have similar separation between their 120-128GB and 240-256GB variants, but their lower-capacity models are comparatively slower. So is the Intel 320 Series 40GB, which offers only half the performance of the 120GB drive. That's still enough to come out ahead of the Caviar Black overall, though.
Now, for the real magic. We can plot this overall score on one axis and each drive's cost per gigabyte on the other to create a scatter plot of performance per dollar per gigabyte.
Want to make the case for splurging on a high-capacity SSD? In addition to offering the best performance, they tend to have the lowest cost per gigabyte. That justification is sound for all but the Intel 320 Series, whose mid-range entry costs less per gigabyte than the high-end model.
At every capacity point, the Intel SSDs are simply too expensive to offer good value. The Corsair Force GT's commanding performance certainly warrants the attached price premium, while the Force 3 looks like a better deal overall than the Crucial m4 at each and every capacity point.
Even with today's flood-inflated prices, the Caviar Black offers a much lower cost per gigabyte than any SSD. It's slower than the solid-state drives, of course, and by huge margins.
Although this analysis is helpful when evaluating drives on their own, what happens when we consider their cost in the context of a complete system? To find out, we've divided our overall performance score by the sum of our test system's components. Those parts total around $800, which also happens to be a reasonable price for a modern notebook.
Despite their lower costs per gigabyte, the high-capacity SSDs still add more to the total cost of a complete system. If you connect the dots for each drive family, you'll see they now drift off to the right rather than to the left. Even the Intel 320 Series is in step this time around.
As part of the cost of a full build, the minor price differences between the SSD families shrink to near-irrelevance, at least for the 40-64GB and 120-128GB models. Those capacities all line up vertically, making it easy to crown the Force GT at the top of each stack. The picture is a little more muddied for the higher-capacity drives, but the Force 3 and GT are particularly well placed.
Looking at the value equation from this angle puts mechanical storage in a different light. If capacity isn't a concern, you can get a good SSD for less than the cost of a mid-sized hard drive.