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Capacity

Solid State Drives (SSD) known as “flash memory” devices are generally based on a technology known as NAND flash. It is common that the user capacity reported by the user’s computer system or device does not match fully with the advertised capacity. There are a number of reasons for this.

Computer storage companies label storage capacities based on the decimal system while computer systems such as Windows report storage capacities based on binary system.(Since OS X Snow Leopard Apple report storage capacities based on decimal system)

Decimal SI Definition Binary IEC Definition
1000 (103) kB – Kilobyte 1024 (210) KiB – Kibibyte
1 000 000 (106) MB -Megabyte 1 048 576 (220) MiB – Mebibyte
1 000 000 000 (109) GB – Gigabyte 1 073 741 824 (230) GiB – Gibibyte
1 000 000 000 000 (1012) TB - Terrabyte 1 099 511 627 776 (240) TiB – Tibibyte

 


For Solid State Drives (SSD) we expect the following amount of user capacity to be reported by Windows operating systems :

Nominal Capacity Minimum Reported Capacity (typically will be higher)
256GB approximately 230.4GB
512GB approximately 476GB
1TB (1,024GB) approximately 953GB

For Hard Disk Drives (HDD) we expect the following amount of user capacity to be reported by Windows operating systems:

Nominal Capacity Minimum Reported Capacity (typically will be higher)
500GB approximately 465GB
1TB (1,000GB) approximately 931GB
2TB (2,000GB) approximately 1,862GB
3TB (3,000GB) approximately 2,794GB
4TB (4,000GB) approximately 3,725GB
5TB (5,000GB) approximately 4,657GB
6TB (6,000GB) approximately 5,587GB
8TB (8,000GB) approximately 7,452GB
10TB (10,000GB) approximately 9,536GB