|OCZ Apex 120GB SSD OCZSSD2-1APX120G|
|Reviews - Featured Reviews: Storage|
|Written by Olin Coles|
|Thursday, 29 January 2009|
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Apex SSD Internal Components
To the untrained eye, the OCZ Apex SSD looks like every other Solid State Drive you've seen with the internal components exposed. Look a little closer, and you will see one subtle difference: two SSD controllers. Previous SSD products from OCZ (and nearly everyone else on the market) have used a single internal SSD controller to maintain the wear-level algorithm and drive firmware. Using a pair of JMicron JMF602B SSD controllers to organize two banks of Samsung K9HCG08U1M DRAM modules into a JMB390 controller, the new OCZ Apex Series SSD offers an impressive capacity with internal RAID-0 performance to subdue stuttering.
Intermittent and delayed response cycles (stuttering) from Solid State Drive products is not wide-spread, but it has become a big issue among the most affordable SSD products. Consumers first experienced the bitter taste of stuttering SSD performance with the OCZ Core Series (v1) SSD, although it has also been reported with the G.Skill MLC SSD and Patriot Warp v2. The phenomenon occurs when the drives buffer is filled faster than it can read or write data, and was prevalent among first-generation JMicron JMF602 SSD controllers.
By taking two separate collections of multi-layer cell (MLC) DRAM modules, the OCZ Apex Series SSD can work like as if there was a pair of Solid State Drives inside.
The internal DRAM is comprised of Samsung K9HCG08U1M-PCB00 IC parts, which bare the branding mark K9HCG08U1M PCB0. These lead-free RoHS-compliant 48-pin ICs are multi-layer, with one IC directly atop another. Each IC has an operating voltage of 2.7-3.6V, with a 25ns speed rating. The K9HCG08U1M parts offer 64GB in 8x organization.
While the JMicron SSD controller is not particularly favored among enthusiasts, JMicron has gone to great lengths to ensure that new products help build a better reputation. The JMF60 and JMF602 chips have been the culprit behind stuttering performance in several products, but this third-generation JMF602B revision improves write latency performance while adding 16KB of on-die cache. JMicron is expected to reveal a successor to the JMF602B sometime in late 2009, which will feature a larger DRAM cache expected to completely solve stuttering and performance issues.
The OCZ Apex SSD uses two of these SSD control chips, which combine efforts and connect into the JMB390 RAID controller.
Having a RAID-like architecture is nothing new to SSDs, but actually having a RAID controller chip is. The OCZSSD2-1APX120G features the JMicron JMB390 RAID controller, and combines the pair of JMF602(B) SSD controllers into a RAID-0 striped array.
This new internal RAID-0 architecture boosts read performance up to 230 MBps and write bandwidth up to 160 MBps, while data reliability is maintained by the internal 15bit BCH mode.
The spare blocks allocated from the total capacity can be altered by drive firmware, and the larger the spare block reservation the less likely performance is affected by over-saturated system data during host-based writes. Although first-generation OCZ Apex SSD products maintain a basic reservation, the premium-branded OCZ Vertex series offers an enhanced 64MB cache in addition to the spare block allocation.
EDITORS NOTE: Because of the internal RAID-0 architecture, Benchmark Reviews has experienced problems with drive imaging programs that write to the 0-sector of the drive (such as Symantec Ghost). Partition images do not pose the same problem.
In the next section Benchmark Reviews begins the performance testing on the Apex Solid State Drive, and we determine just how well the OCZSSD2-1APX120G compares to the best-performing competition.