Old dog, new tricks: OCZ Vertex 2E reviewed
The OCZ Vertex 2 just got extended. The newer Vertex 2E features a new firmware that promises better performance and delivers additional usable capacity. We will take the new SSD for a spin and see what improvements there are to be had.
Most Solid State Drives on the market now are based off MLC NAND flash and feature a controller from either Intel, Indillinx, Jmicron or Sandforce.
Whilst offering fairly good performance for a significantly lower cost as compared to SSDs using DRAM or SLC NAND flash, MLC NAND flash presents several problems when put to use in an SSD.
First of all, MLC NAND flash has a write cycle lifespan that is significantly lower than SLC NAND flash. Hence, a MLC flash controller needs to practice wear levelling to spread the writes out amongst the cells.
Secondly, MLC NAND flash needs to be accessed in blocks. Changing just one bit in a block necessitates reading of the entire block by the controller and writing the entire block back in place. These additional actions result in access time penalties and more data written that is necessary – a factor otherwise known as write amplification and results in further detriment to the lifespan of the SSD.
Various differing methods are used by the SSD controllers to get pass these problems. Clever algorithms coupled with larger DRAM cache tend to reduce the small write performance penalties involved.
The firmware and by extension, the algorithms involved, are arguably the heart and core of every SSD.
Here, Sandforce controllers deserve a special mention since it does not use a DRAM buffer – instead, it uses over provisioning of the NAND flash and clever compression tricks to greatly improve write performance. This compression also reduces the amount of data actually written to the flash and acts to improve the lifespan of the SSD as well.
Old dog, new tricks?
Today, we will look at OCZ’s latest SSD, the Vertex 2(E). Physically identical to its older brethren, the Vertex 2, the Vertex 2E is based on the exact same hardware – 128GB worth of NAND flash coupled with a Sandforce 1200 series controller.
The trick, you see, is the new Sandforce 1500 firmware that is loaded onto the same hardware.
Touted to deliver up to 50K IOPS for 4K random writes and 285MB/s read performance, the Vertex 2E looks very appealing indeed.
Furthermore, the SF1500 firmware also brings with it additional usable capacity by reducing the amount of over-provisioning of NAND flash.
The end result – OCZ’s Vertex 2E has increased usable storage space by 20% compared to the older Vertex 2.
It looks like you can teach an old dog new tricks after all.