With the latest SSD controller from SandForce, the SF-2281 SATA III, we have been seeing two different types of flash memory used as the storage medium depending on which vendor or product line you look at.  Asynchronous flash and synchronous flash differ in their timing when sending read and write commands, [H]ard|OCP’s analogy of synchronous flash working like DDR is perfect as the new variety can send a command on both the rise and the fall of a clock cycle.

The reason this now matters is SATA III, which allows enough bandwidth for synchronous flash to show off its higher speeds; with the previous SATA standard it simply had no impact.  That speed impact on the new standard becomes obvious in [H]’s testing, especially when they fill both drives half way and conduct some real world tests.  Now that some of both types of drives are on the market, they also look at the price difference between the two types of flash,; a comparison in which the old asynchronous flash does not look good coming out of.

"News flash! All flash NAND is not created equal! Sure, you know about multi-level and single-level NAND when it comes to speed, but what about synchronous and asynchronous NAND inside your shiny new SSD? We have answers and tell you where your money is best spent for real data speed."

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