It is correct. 1048 bytes per megabye storage. Take the 250 gig and divide it by 1.048 bytes x 250 gigs = 239 (more or less). Drive manufacturers usually report drive capacity in millions of bytes, whereas your BIOS and FDISK usually report the capacity in megabytes. One megabyte equals 1,048,576 bytes (or 1,024K, wherein each kilobyte is 1,048 bytes). So the bottom line is that this 2500M drive also is a 238.5gig drive! What is really confusing is that there is no industry-wide accepted way of differentiating binary Megabytes from decimal ones. Officially they are both abbreviated as M, so it is often hard to figure which one is being reported. Usually drive manufacturers will always report metric megabytes, since they result in larger, more impressive sounding numbers!
I know, now you have a headache!!!
Update: I even confused myself! LOL (not really)
Math: Given 1 megabyte = 1048 bytes. So divide the 250 gigs by 1048 = 238.5 Still painful!!!

but the 8 mg cashe is actually
7.63gigs...enough!!!