Hi,
i have purchased a brand new Corsair F60 SSD two weeks ago and installed Windows 7 Professional x64 on it. Some diagnostic tools are telling me that there are 256 defective sectors on the ssd. Here a screenshot of HDtune Pro:
I read somewhere that HDtune isn't able to read ssds properly. However Intel SSD Toolbox also shows me these 256 defective sectors. This is my first SSD, so i am no expert with these. Should i RMA the disk or is this normal for SSDs?
Flash chips when they come from a factory aren't guaranteed to work perfectly. Flash memory chips are sold even if a certain number of sectors are defective, up to a certain limit.
It's like LCDs and dead pixels - if no dead pixels were allowed, the screens would be too expensive for general use - but you can pay more for a perfect screen, e.g. for scientific, graphic design or medical use. If flash had to be perfect, it would be too expensive - but you can pay more for better tested 'enterprise grade' flash.
It is up to the manufacturer of the SSD, memory card, memory stick, etc. to test the flash chips, and find out which sectors are dead. When an SSD is built, the manufacturer tests the flash to find out which sectors are bad. The SSD controller records the list of bad sectors - this could be several thousand bad sectors on a big SSD - and instead of using those sectors uses some spares. These are reallocated sectors.
Normally before the drive leaves the factory, the manufacturer will zero out all the SMART values. So, even if the drive was built with 4000 bad sectors which have been reallocated, SMART will still read 0.
However, once the drive leaves the factory, if it discovers and swaps out any more sectors, they will go in the SMART count.
So, how can a brand new drive show up bad sectors in just a few weeks. It's most likely because the manufacturer only runs a very basic test at the factory - this will catch catastrophic problems, like a dead chip, or an unsoldered PCB trace - but slightly flaky sectors on a mostly good chip could easily be missed. And it's not until the drive is installed in a PC and given a proper workout with lots of installation, file saving, swap filing, etc. that all the bad sectors will be recognised and swapped out.
In your case, you've got 256 bad sectors, which have been swapped out for good ones. Most flash memory is built in 'blocks' of 1 MB - with individual 4k sectors. The most likely explanation of 256 reallocated sectors is that a whole 'block' of flash is faulty - probably due to a manufacturing flaw that just happened to land on a control circuit that operates the whole block.
This is much less of a problem than on mechanical hard drives. On mechanical hard drives, there is a bit of a worry if lots of 'reallocated sectors' start appearing - as this can indicate that the mechanical structure of the drive is degrading. In particular, one fault on a hard drive platter, can't wreck 200 sectors in one go (or rather, if it did, it would have been spotted at the factory). If 200 bad sectors suddenly appear on a mechanical drive, it suggests some serious damage has occured, which is at high risk of destabilising the rest of the drive.
On flash, a fault affecting one part of one chip can't destabilise the rest of the drive - so, all it's telling you is that the flash chips have sustained some minor damage - the most likely explanation for which is that they came from the factory with some minor (but still in-spec) damage, which was so minor that it wasn't noticed during the factory tests.
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