Since the beginning of the year, new SSDs have hit the market, mostly from Samsung and OCZ. While waiting for the OCZ Vertex and its new Indilinx controller, we put two other new SSDs through their paces:
- The Samsung 256 GB PB22-J, which is the second generation of Samsung MLC SSD
- The 120 GB OCZ Apex, an SSD that couples two Jmicron type MLC SSDs
We aren’t going to go back over what SSDs are or aren’t here but refer you to our first article on the subject.
Samsung PB22-J (MMDOE56G5MXP)In comparison with the previous generation, the improvements are obvious. The controller, still an ARM type CPU, is much larger, with double the number of channels addressing the MLC NAND Flash chips. The cache is now 128 MB and is DDR-SDRAM.
In terms of the chips, there are 32 with 8 GB on each. They take up 16 spots on the PCB, each pair being stacked. The forthcoming OCZ Summit is a version of this SSD.
Note that although the 256 GB and 128 GB versions display identical performances of 220 MB/s read and 200 MB/s write speed, the 64 GB version drops to 120 MB/s.
With its Apex, OCZ is bringing in a new design as this is in fact a two-in-one SSD! The SSD includes two of the infamous JMF602 controllers on the same PCB, interfaced with a JMB390 chip and each handling 8 MLC NAND Flash Samsung chips.
The JMB390 chip utilizes a RAID-0 configuration (stripping), this RAID recognized as a standard drive by the system. This type of array allows you to double sequential read and write speeds fairly simply and in theory it is possible to go much further: the JMB391 allows you to do the same thing with 4 SSDs and the JMB392 with 5!
Note that the TITAN T.Skill SSD uses the same design. The 250 and 120 GB versions are announced at 230 MB/s read and 160 MB/s write, as against 110 Mb/s write for the 60 GB version.