Losing 7% on each hard drive

[technodean]

Hello, Just wondering how every hard drive on my pc loses around 7%, I have an 80gb sata, a 300gb sata, 1tb usb. When I load speed fan they all come up saying 80.1, 300, 1000.1gb. However defrag states size as 74.55gb, 279gb, 932gb.

 

[bdcrlsn]

Most operating systems, including the Microsoft Windows operating systems use the powers of 1024 convention when reporting HDD capacity, thus a hard drive offered by its manufacturer as a 1 TB drive is reported by these OSes as a 931 GB hard drive.

 

[technodean]

Thanks bdcrlsn, was curious of why this was happening. Thought it may have been a setting I may have had on.

 

[mrmez]

Not entirely correct.

No HDD you buy off the shelf should not include ANY OS pre-installed.

You lose the capacity due to formatting.
Formatting breaks the disk up into smaller, more manageable sectors, but doing so does take up space.
Depending on what you format your disk for, FAT, NTFS, OSX, etc etc, you will lose more or less space. Disk manufacturers obviously don't take this into account when making or labelling their drives, nor should they.

SSD's are even worse. Not only do you lose space to formatting, but space is also set aside for cells that are expected to fail. You can expect ~90% usable space once the drive is ready to go.

Yes this IS a form of cheating (since the drive is essentially unusable without formatting), but since everyone does it by the same amount, its not really a big deal.

 

[funnyman06]

As bdcrlsn was saying, when HD manufactures claim HD size they estimate with 1000MB/GB, 1000GB/TB, 1000KB/MB etc... But in the real world we know that there are 1024 B in a KB, 1024 KB in a MB, so on and so forth. That is what you are seeing, you're not loosing HD space, its just a difference in definition.