Differance between HDD and SDD drive size allocation

[MichaelOz]

With every traditional HDD I've purchased I always tend to loose a chunk of it, once I've formatted the drive. For example 1TB drive from shop ends up having 930GB usable space after NTFS format.

However with my 60GB SSD, the full total of the drive is available after formatting.

What exactly is the difference?

Thanks

[tachi1247]

It's a combination of how the drive is marketed and how much "spare" space is set aside for the drive to use. Traditional hard drives define GB as multiples of 1000 and computers have always classified them as multiples of 1024. That is where you extra space disappears to on a traditional HDD.

OCZ and some others have decided to finally end the confusion and list GB using the same basis that the computer uses to determine size. In reality, there is more than 60GB of nand flash on the disk, but only 60GB is usable to you as the controller requires some spare area in order to work. Different manufacturers set aside a different amount of nand depending upon their unique controller.

It's just like CRT monitors back in the day a 17" monitor would have 16.1" viewable. When everyone switched to LCD they finally started listing the viewable size.

Edit: some manufacturers such as Kingston are still classifying their drives using the same basis as a traditional HDD. A 64GB V+ series drive will not have 64GB of formatted capacity. You will have to read the fine print to figure out exactly what the size will be for each drive, but in general, the drives that are not traditional "computer" sizes will have a formatted capacity of their listed size. ie 60Gb instead of 64, 120 instead of 128, etc.

[Zanson]

Edit: some manufacturers such as Kingston are still classifying their drives using the same basis as a traditional HDD. A 64GB V+ series drive will not have 64GB of formatted capacity. You will have to read the fine print to figure out exactly what the size will be for each drive, but in general, the drives that are not traditional "computer" sizes will have a formatted capacity of their listed size. ie 60Gb instead of 64, 120 instead of 128, etc.

Intel seems to have done this as well.. the 80GB drive i have is only 74.5GB. hopefully they will follow suite and change to the 1024 multiplier...