OCZ has stated before that it delayed its Vertex drives due to firmware upgrades. DailyTech has now learned more details on why OCZ held back shipments of its flagship SSD drives.

The latest firmware for OCZ's Vertex series boosts sequential read and write performance, so much so that it can compete with Intel's X-25E Extreme series on performance. However, the Vertex boasts a much greater capacity and a much lower price.

The Vertex series, which uses an Indilinx Barefoot SSD controller, was originally specified at 200MB/s sequential read and 160MB/s sequential write. However, OCZ's internal tests show up to 250MB/s sequential read and 240MB/s sequential write speeds.

These tests were conducted on an empty drive, and will not officially be presented to consumers. However, it gives an indication of how fast the final drives will be and allows some results to be inferred.

While the firmware is responsible for a large part of the improved performance over the introductory specifications, it is only because of the hardware that it is able to work with. The 120GB and 250GB drives have 64MB of DRAM cache and more channels to access its MLC NAND flash, whereas the 30GB and 60GB drives only have 32MB of cache.

It should be noted that OCZ rounds down its capacities for several reasons. Most storage vendors show capacity in decimal format, whereas Windows show capacity in binary format. This means that the reported capacity is lower than what is on the label.

Most SSDs also reserve some capacity for redundancy in case of bad sectors, and also for wear leveling. These reserved areas may occupy up to five percent of an SSD's storage capacity.

Prices are also coming down, as more production of 16Gb and 32Gb NAND flash comes online at smaller process geometries.

OCZ will post official specifications and revised MSRPs when it ships the Vertex series later this month.
   

 *Unofficial specifications, subject to change