Why does my 3TB WD my book essential shows only 2.72TB on Vista?

HI, i recently bought WD My Book Essential 3TB and when i plug it it, it shows only 2.72TB free space? where does the 200GB gone to??! 200GB!! thats like alot… i would like to know whther the smartware takes up alot of space…

plus, theres several files inside the drive whch is preloaded when i bought it…WD stuff. can anyone help me explain why theres so much disk space lost? or if anyone having the same problem? thank you in advance.


It’s probably the firmware. The drives a while ago came with the annoying VCD used about 500 M or more. Also the way the convert bytes. A 1T drive is about 931G not 1000


thank you for your reply…  so if its the firmware, should i update it or just leave it as it is? i think the firmware should be the updated one already isnt it? since i just bought it…hw do i check whether the firmware is outdated?

your right about previous drives, even pendrives that shows 4gb doesnt always be 4gb… sometimes its 100/200MB less…the thing that got me annoyed is that my hard drive lacks almost 200GB!! thats alot. i could put in appx. 60 HD quality movies in there…haha.

I would not update the firmware unless you had a problem that it addressed. The updates can cause theirown problems. If it ain’t broke don’t fix it is best here.


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Apparently nowadays HDD is marketed using “Marketing” sizing.

3TB “Marketing” size  = 3,000,000,000,000 bytes instead of 3,298,534,883,328 bytes.

3,000,000,000,000 bytes / 1,024 = 2,929,687,500 KB

2,929,687,500 KB / 1,024 =  2,861,022 MB

2,861,022 MB / 1,024 = 2,793 GB

2,793 GB / 1,024 = 2.72 TB

I have just bought WD My Book Essential 3TB USB 3.0 WDBACW0030HBK-NESN.

Windows XP drive properties shows the capacity = 3,000,557,891,584 bytes = 2.72 TB.

Same thing happens on my “320GB” Seagate internal drive.

Windows shows 320,000,000,000 bytes / 1,024 / 1,024 / 1,024 = 298 GB instead of the expected 320GB.

Some of it is because of the firmware on the bridge board. Back when they used the annoying VCD it was taking 500-600 meg. I think the bridge board takes it’ space just like an integrated video card takes from ram.


hey, thanks for the explaination… it now makes sense… yeah i guess WD has its own marketing strategy…by displaying 3TB but actually its 2.72TB… nonetheless im stil happy with it…maybe next time il think of the ‘marketing’ sizing before buying…