04-08-2009, 03:03 PM

I ordered and just recieved a new mac book w/ OS X leopard, 2.4gtz, 4 G ram, and i ordered it to have a 320GB Serial ATA hard drive @ 5400 rpm. when i look at the my computer's info, i am told that my hard disk only has 298.2 G capacity. is this normal? Also, i cant seem to find anything that tells me the rpm. Where can i find this information on my mac?

any further insight would be greatly appreciated.

04-08-2009, 03:10 PM

Originally Posted by technique00

I ordered and just recieved a new mac book w/ OS X leopard, 2.4gtz, 4 G ram, and i ordered it to have a 350 Gig hard drive at 5400 rpm. when i look at the info on my computer, i am tolf that my hard disk only has 298.2 G capacity. is this normal? Also, i cant seem to find anything that tells me the rpm. Where can i find this information on my mac?

Welcome to every hard drive ever.

This is because the hard drive manufacturers say a gigabyte is 1000 megabytes, and 1 megabyte is 1000 kilobytes, rather than 1024 kilobytes.

At the kb level, you lose 2.4% (24/1000). At the mb level, you lose 4.8%. At the gigabyte level, you lose 7.2%. 350 gb * 92.8% = 32.5 gb, minus a few for the operating system. So yes, it is normal.

As for the RPM,

Apple menu -> About This Mac -> Serial-ATA

You'll have to copy/paste your hard dive model # and do a bit of searching, but I'm sure you'll be able to find it.

04-08-2009, 03:14 PM

the space is absolutely normal, it's just marketing and games with numbers ... it has to do with the fact that a megabyte has 1024 bytes and not exactly 1000 ... it will be the same with any hard drive you buy

Edit.
cheers miles got it before I did, more accurate even

04-08-2009, 03:16 PM

You can use the calculator here to calculate the size of your hard drive as it actually is. So, for your example, your 320GB HD is 298.0232238769531MB.

04-08-2009, 03:22 PM

You also posted the HD rpm. 5400.