What is the difference between a "Genuine Gigabyte" and a "Marketing Gigabyte"?

Question

What is the number difference between the two?

For example, when someone advertises a computer, and they say it has 250 GB, that is not the real amount of GB it has. That is just a rounded number. So how many Genuine GB's would a "250 GB" computer have? And what is the percentage difference?

Answer 1

Don't listen to the answers that say there is "hidden" space being used when you format or other whacky answers like that saying you lose space. I'll explain. It might be a lot of math, so brace yourself!


Computers work in binary not decimal. That's 0's and 1's when you break it down to the transistor level. So when you get to a kilobyte, it's not 1000 bytes, it's 1024. This is because of binary which uses base 2 and not base 10 like decimal. 1024 is the first multiple of 2 above 1000.

So in turn:

1024 bytes = kilobyte
1024 KB = megabyte
1024 MB = gigabyte
and so on...

By the time you get to the gigabyte level, you're working with 1024 ^ 3 which is 1,073,741,824 bytes. Hard drive manufacturers, though, have always sold drives based on the decimal system, which assumes there is 1,000,000,000 bytes in a gigabyte. But we know the true number now, as I've pointed out, therefore it's a loss of 73,741,824 bytes for each gigabyte.

So if you have a 250GB drive like in your case, they're only reporting 250,000,000,000 bytes. But when you do the math, it's only 232.83 GB in binary which is what a PC understands. So it looks like a loss of 17GB, but in reality, the hard drive manufacturer never sold you 250 true gigabytes. So in your terms, that's the "genuine" versus the "marketing".

Hopefully that makes sense.

Answer 2

In "Genuine" terms, a Gb is 1024 Mb, a Mb is 1024 kb, and a kb is 1024 bytes. So a Gb is actually 1024^3 bytes, or 1,073,741,824 bytes..

In "Marketing" terms, a Gb is 1000 Mb, a Mb is 1000 kb, and a kb is 1000 bytes, so a Gb is 1,000^3 bytes, or 1,000,000,000 bytes.

The two are usually close enough that it doesn't really matter.

250 Marketing Gb is actually 250,000,000,000 bytes, which is 233 Genuine Gb, so the difference is about 7%.

Answer 3

In computer science, 1 GB = 1024 MB , 1 MB = 1024 KB , 1 KB = 1024 B .... while in the marketing .. 1 GB = 1000 MB , 1 MB = 1000 Kb , 1 KB = 1000 B

Answer 4

There is always some space on every kind of drive (CD, DVD, Removeable Media Key, Hard Drive, etc) that you do not get to use. With hard drives that run windows that part that you cannot use does not always mean that windows is using it. All drives have cetain things they need to tell the computer about how to use them. My 256MB memory card uses about 15MB to tell the computer what it is called, how much memory it holds, and a registery telling the names of files on it and how to find them.

Answer 5

Yep, its not always the full amount of space. When formatted some space is used for windows.

Answer 6

2.4 % actual 250gig = 256gig.