1.8" Drive - is 40 GB faster than 60 GB?

[wking]

I read somewhere that there is a slight speed difference in the 40 GB vs 60 GB drives for the X-series. I did an extensive search of several sites but can't find what I think I read...

I know they are both 4200 RPM, but perhaps there is a slight difference in access time?

Does anyone know if size matters in terms of data transfer speed and if so is bigger better?

[richarddd]

As I undertstand it, if the only difference between two drives is the capacity, the larger drive will be faster.

[bhtooefr]

Assuming the same number of platters, the 40GB HDD will have a lower density, and therefore the head will have to move further to get to a specific bit. That takes longer.

[whizkid]

You would have to find the drive data sheets to be certain. Most driver makers have them available on their web sites.

But since I'm a geek, I'm going to spout on about how it could be.

If these drives are in the same family, meaning same electronics and head motors...

The larger drive could have another platter. 3 heads isn't uncommon in 2.5" drives, maybe they do it in the smaller drives too. In that case, you'd have no difference in speed.

If the platter is higher density... That density is an areal density, not linear, so we can't know (without spec sheets) the densities of tracks per inch and bits per inch along the track. If the density is solely due to tracks per inch (which it isn't), you would see no speed improvement. If it's due solely to bits per inch (which it isn't), you'd see up to a 50% improvement (60/40 = 1.5).

But it's just a lot easier to read the spec sheets.

[aamsel]

Well, the data sheets are at:
http://www.hitachigst.com/hdd/support/c ... k60_ce.htm

The 20 and 30GB versions have 1 disk, and the 40 and 60GB versions have 2 disks.

So...they each have 2 disks, so the density is higher on the 60GB version than on the 40GB version.

Andrew
Austin, TX