OCZ Vertex 4 Solid State Drive 512GB / 256GB Review
The Vertex 4 Series SSDs
OCZ has retained the same SSD casing design on the Vertex 4 series that we saw on some older models. It has a plastic top with branding sticker and the base, extending to the sides, is a brushed metal. On the base the SATA3 power and data connectors are visible as are the four holes used for installation in a case or laptop.
Inside the drive we see an interesting PCB. The most notable difference between this and older models is that it features a connector at both ends. One for standard SATA 3.0 connections and the other for mini-PCIe which will please system builders.
For this generation of drives OCZ and Indilinx are introducing the Everest 2 controller. Branded IDX400M00-BC it sits near the centre of our PCB, surrounded by drive cache (Micron) and eight Intel MLC NAND flash chips with a further eight on the base. These are configured to give the Vertex 4 476GB in Windows 7 for the 512GB model and 238GB on the 256GB model, matching the usable capacity of drives such as those based on Marvell controllers.
Built into the Everest 2 platform is Ndurance 2.0 technology which looks to extend the lifespan of OCZ SSDs past that possible on other platforms and is the result of work with NAND manufacturers to minimise the effects commonly associated with newer chips (fewer program/erase cycles, increased cell disturbance, shorter retention times). Ndurance 2.0 is designed with enterprise class endurance even when consumer NAND chips are used and features multi-level Error Code Correction (ECC) and Redundant NAND Array (RNA) capabilities along with adaptive NAND flash management. It is also designed to reduce write amplification without the performance hit which is associated with data compression. (Write amplification is reduced without compression by keeping multiple write requests within the host, reducing wasteful copy back operations on unaffected sectors and preserving the NAND cells in the process)
As an example of the extended reliability OCZ state that Ndurance 2.0 with its Flash Transition Layer (FTL) combined with voltage shifting and signal processing can achieve correction power of 128 bits per 1KB of data. This exceeds the requirements for current and next generation NAND flash devices while reducing uncorrectable bit error rates (UBER).
OCZ rate their Everest 2 based 512GB drive at 535MB/s read with write at 475MB/s. The 256GB version sits at 535/380MB/s and for IOPS performance (which we have verified) the 512GB model tops out at 120,000 with 90,000 Random 4KB Reads and Random Writes up to 85,000.
Returning to the features for a moment the drive supports AES-256 encryption and the inclusion of Ndurance 2.0 means this high IOPS performance can be enjoyed for a significant period of time with OCZ leading the industry by using a 5-year warranty on Vertex 4.