"Matthew Nuzum" <[EMAIL PROTECTED]> writes: > So if you all were going to choose between two hard drives where: > drive A has capacity C and spins at 15K rpms, and > drive B has capacity 2 x C and spins at 10K rpms and > all other features are the same, the price is the same and C is enough > disk space which would you choose?
> I've noticed that on IDE drives, as the capacity increases the data > density increases and there is a pereceived (I've not measured it) > performance increase. > Would the increased data density of the higher capacity drive be of > greater benefit than the faster spindle speed of drive A? Depends how they got the 2x capacity increase. If they got it by increased bit density --- same number of tracks, but more sectors per track --- then drive B actually has a higher transfer rate, because in one rotation it can transfer twice as much data as drive A. More tracks per cylinder (ie, more platters) can also be a speed win since you can touch more data before you have to seek to another cylinder. Drive B will lose if the 2x capacity was all from adding cylinders (unless its seek-time spec is way better than A's ... which is unlikely but not impossible, considering the cylinders are probably closer together). Usually there's some-of-each involved, so it's hard to make any definite statement without more facts. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq