Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

My SSD which was manufactored this year has a sector size of 512 bytes. Can it be changed to 2k or 4k while keeping the data. Using Windows 7. I want to benchmark and see if bigger sector size increased read/write speed.

share|improve this question
I really doubt it has a 512 bytes sector size. It probably displays that size to windows (or any OS which queries it), but internally it will have quite different. – Hennes Jul 21 '12 at 18:20
512 use to be the default cluster size. – surfasb Jul 24 '12 at 2:26

While not truly sectors - because SSDs are not circular - the memory cells of an SSD are grouped into pages of 4 kB each. Pages are in turn collected in blocks of 512 kB (still not 512 bytes though).

Remember that SSDs cannot write to non-empty memory, but must clear entire pages of memory at a time, temporarily moving data to another location and back after the page has been cleared. This is why the TRIM command and garbage collection are important to keep an SSD in good shape.

I would guess that increasing the page size would increase the write overhead when the drive runs out of empty pages. Also, there really shouldn't be any benefit to reading more data at once, because of the low access times involved, as opposed to a rotating harddrive where you want to read as much as possible while the head is in the right place.

share|improve this answer
This varies widely from drive to drive. – psusi Jul 21 '12 at 22:25

The 512B sector size reported by the SSD is only for compatibility purposes. Internally data is stored on 8kiB+ NAND pages. The SSD controller keeps track of the mapping from 512B to pages internally in the FTL (Flash Translation Layer).

I know that at least the SandForce SF-2600 controller supports various sector sizes, but to change the sector size requires a change in the firmware, which only the manufacturer can do. This is not something you can change after the fact, even if you were to have an SSD that supports other sector sizes.

share|improve this answer
I think you can change it after the fact if supported by the vendor: Also seems like a good idea - otherwise won't the OS send multiple commands for a single read/write? – Sam Brightman Sep 19 '15 at 10:44

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .