The Toshiba OCZ VX500 (256GB, 512GB, 1024GB) SSD Review

Final Words

The VX500 has a very different performance profile from the Vector 180 it replaces. This isn't always a bad thing: in many ways, the Vector 180 behaved more like an enterprise SSD with an emphasis on sustained performance. The VX500 by contrast is very clearly focused on peak performance for client workloads. It is one of the few drives that uses SLC caching on MLC NAND, and this allows it to deliver very good burst performance by the standards of a mid-range SATA drive. But as we saw with the Crucial MX200, SLC caching on an MLC drive has a downside for sustained workloads. Once the SLC cache fills up, the drive has to divide its time between flushing the cache and serving new requests. This produces a noticeable drop in performance, though not as severe as for the MX200 or many TLC drives that are even more dependent on their caches.

The impact this has on benchmark performance varies widely depending on the drive and the test, and often unpredictably because there is currently no mechanism to directly monitor the state of a drive's internal caches or the progress of flushing that data from SLC to MLC (or TLC). The 256GB VX500 suffered toward the end of the random write test due to its SLC cache suddenly filling up, while the 1024GB VX500 occasionally sped up significantly during the sequential write test due to the background garbage collection process catching up enough to allow a few minutes of writes into cache. These oddities are unlikely to be encountered during ordinary use. Based on the VX500's strong performance on our trace-based ATSB tests that play back real-world I/O patterns but with shortened idle periods, it appears that the VX500 only needs a little bit of idle time to maintain good performance. That means that the most important performance shortcoming is probably the low random read speed, which is almost as slow as planar TLC SSDs.

The VX500 is also very energy efficient, in many cases rivaling the record-setting Crucial BX100. This is a huge change from the Vector 180, which has no support for SATA link power management and significantly higher load power consumption. The one exception is the idle power management of the 1TB VX500; most likely due to its use of an external DRAM buffer, it does not power down as much when entering the slumber state and does not support the deepest DEVSLP state.

The end result is a drive that is well suited for use as a mainstream SATA SSD. Technologically, it's a stopgap product using off the shelf components, but it addresses the most relevant weaknesses of the Vector 180. Otherwise the VX500 will probably have a relatively short life in the market before being replaced by a 3D NAND product with a completely different and far more modern controller.

The initial MSRPs put the VX500 near the top of the price band for mainstream SSDs, but it could come down significantly. The OCZ Trion 150 debuted early this year with a relatively high price for a budget planar TLC drive, but has now become one of the cheapest options and a good value for that segment. If the VX500 can similarly come down a bit from MSRP then it may enjoy some time as a decent mainstream option while the 3D NAND choices are still limited. At MSRP, the OCZ VX500 would be too close to the Samsung 850 EVO in price, and the latter drive is a much better all-around performer. Below that price point, the closest competitor in performance would be MLC+Phison S10 products like the PNY CS2211, given that the rest of the MLC options are either being phased out or are already more expensive. The CS2211 is faster than the VX500 on enough tests to make it a slight favorite, but the VX500 is the better pick where battery life is a concern.