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Poor quality controllers to blame, says Samsung

DailyTech reported several days ago that SSD manufacturers have been having problems with Samsung's latest generation of 32nm NAND flash. The new chips have slow write speeds, thus making them unsuitable for use in SSDs since that is one of the major advantages that the new drives have over conventional hard drives. 

We have received a reply from Samsung confirming the issue, stating that "for quality SSDs, every NAND process geometry upgrade requires a matching upgraded controller.  Should (Samsung's) 30nm-class NAND be used with a conventional controller of insufficient quality, performance slowdowns are indeed possible".

Flash memory stores information in arrays of memory cells made from floating-gate transistors. As these transistors scale to smaller process geometries, it becomes harder for electrons to flow. This sometimes causes errors in writing to memory cells which must be corrected through ECC (Error Correcting Code). ECC is typically handled on the flash controller, which may be overloaded by excessive write errors if it is not sufficiently powerful enough. This is the most likely scenario for what is happening.

Companies we spoke with confirmed similar problems with 32nm flash from Toshiba that had been overcome. Intel is using 34nm flash from IMFT that was delayed from mass production for six months, possibly due to a similar problem as well.

Most of the SSD manufacturers we spoke with had paired Samsung's flash with Indilinx's Barefoot flash controller. There are several iterations of the Barefoot controller out there for different SSDs, and no doubt Indilinx is working on the problem. However, it might take a while, and sharp price drops on SSDs are unlikely for several months.

Meanwhile, Samsung is currently in the process of completing a new flash controller revision for their own line of SSDs, and have not released any SSDs of their own using the new flash memory. Samsung states: "We spend many months developing and then fine-tuning the controller and firmware technology for our SSDs, working very closely with most of the major PC OEMs".



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RE: Errors?
By ElderTech on 10/4/2009 11:02:59 PM , Rating: 2
Unless you've actually used the latest generation of SSD, particularly those from Intel and OCZ, you can't imagine the improvement in overall performance over conventional hard drives. Due to environmental issues, I have one of the original Intel X25-M G1 versions that has been running flawlessly as an OS drive. Coupled with an i7 processor and other compatible components, it's simply amazing in speed and reliability. And it really makes a huge difference in the noise level of the system! For a comparison, I had originally purchased two Velociraptor 300gb drives to use for the OS, but got rid of them when the Intel G1 arrived and blew them away, both in performance increase and noise reduction.

Additionally, I also have recently added the Intel X25-M G2 drives to laptops with similar success. And at a price of $2.80/gb, it's well worth the money. If you really want to evaluate the current state of SSDs, by far the most technically competent and thorough research and reviews are at anandtech.com. Following is a link to his most recent review, but also be sure to check his archives for other relevant articles including extensive ones like his "anthology" on detailed SSD technology. Here's the link:

http://www.anandtech.com/storage/showdoc.aspx?i=36...


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