Thread: SSD Install
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Old 30th August 2014
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jggimi jggimi is offline
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Oko, performance degradation from sector alignment issues occur when the device sector size is larger than what the device presents to the OS -- whether magnetic, spinning media or NAND (flash) device.

Excerpt from http://en.wikipedia.org/wiki/Advanced_Format regarding 4K devices that present 512 byte logical sectors, applicable to all sector/page sizes.
Quote:
The translation process is more complicated when writing data that is either not a multiple of 4K or not aligned to a 4K boundary. In these instances, the hard drive must read the entire 4096-byte sector containing the targeted data into internal memory, integrate the new data into the previously existing data and then rewrite the entire 4096-byte sector onto the disk media. This operation, known as read-modify-write (RMW), can require additional revolution of the magnetic disks, resulting in a perceptible performance impact to the system user. Performance analysis conducted by IDEMA and the hard drive vendors indicates that approximately five to ten percent of all write operations in a typical business PC user environment may be misaligned and a RMW performance penalty incurred....
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