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Hard drive size incorrect in Windows XP setup (130GB), but correct in BIOS (160GB)

MilkMon asked
Last Modified: 2013-11-14
I have bought a new hard drive for my PC - a seagate baracuda 160GB

The thing is, Windows XP only thinks its a 132GB ...

I have had this problem before with a 260GB ...

... I have checked the BIOS, and it reports it correctly as 160GB - what should I do ?


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Brian PiercePhotographer
Awarded 2007
Top Expert 2008

This is normal !
Actual usable disk space is normally about 10% less than the manuracturers quoted size. This is a the combined effect of binary arithmatic and the fact the often quoted MB, is in reality not 1000 but 1024Kb and that difference adds up, plus the fact that the manufacturers always quote the unformatted capacity and some space is lost to the formatting process.

In my opinion it too much "lost".  From my experience size loss could be 0.93-0.94.
So it must be about 148.8 Gb if the drive marked as 160Gb
Lee W, MVPTechnology and Business Process Advisor
Most Valuable Expert 2013

It's normal for Windows to report less space the what you thought you have based on manufacturer claims, but it's NOT NORMAL to lose 18% of the drive.

AlexNek has it correct in his original links.  Read those and you should be fine.

Hellow Sir. The thing is that the system file has some data to store in the hdd. even for me on my vista os the hdd is 80gb but shows 66 on vista. and the same laptop i changed it with genuine Xp pro the hdd shoes 74 gb. see the diffrence

Hi zaheerabbas_8,
it is normally only for laptops and only for the original distributed HD. Most of suppliers stored OS backup on hidden partition.


I got more problems now anyway - I can't find any of my original XP disks (I must have at least 3, as my 2 x PCs and my Sony Laptop all have the product key stuck on their cases!!!) - but in the absence of the original XP CD I have what is by the looks of it a hookey copy.... as when I try to download SP1 it kicks me out saying it's an illegal version of Windows.

I can buy a new one, but it's like mega expensive ($140 or something) and I'm buggered if I'm going to pay for that psycho freak Gates to get any richer when I've already paid for three versions of his shit software....

..... so I'm in the myre - I feel like just shooting my PC and be done with it.

Any ideas, give me a shout - but I don't think there's an answer to my quandry.

I'll be awarding the points to AlexNek as he's come up with the correct answer - thanks Alex - I was really banging my head against the wall on this one - I had the same problem in England with a 250GB hard drive - I have two of these that I could only use the first 130GB on - so you have really enlightened me.

Even the guy at the computer shop came up with the bullshit about 1024MB and 1000MB LOL - how can 24 out of a 1000 make this amount of difference ? It's like a little over 2% difference conflicting representations of what a MB represents would ever make - LOL !!!!!!!!!

Thanks again

This one is on us!
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Thanks Alex,

Your appeal for clemency on my PC's behalf has been accepted - so my PC thanks you, and will live to p*** me off another day LOL !!!!

Talk to you soon my friend.


Thanks for the solution also.

Don't mention it, Matt + PC :)
Thank you too.
I hope, soon we will hear good news from you.
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