Originally Posted by Ceadderman
Actually the term Deathstar was coined about the Hitachi Deskstar drives after some idiot Seagate Rep bad mouthed their 1 TB 5 platter drives. His claim was that 4 platters are better than 5 which is absolute rubbish because that's more information per platter for the reader to sort through. Where 5 platters has less information stored on them and the information is closer to the edge of each platter. His agenda was clear the moment he flapped his gums about the whole issue. I won't listen to Reps. Those are the last people to be listening to because it's their job to advertise and sell product to the industry.
A 5x200GB platter drive will have lower sequential speeds than a 4x250GB platter drive. The only time this would not be true is if the 5 platter drive were using 250GB platters, and "short-stroked" itself in the firmware. (In which case, why add the extra platter? It just raises the cost and introduces reliability issues.) Velociraptors do that, though - they use a portion of 1-2 2.5" platters.
Most 5 platter drives have reliability issues. Certainly all of Seagate's 5 platter drives did... and all of WD's 4 platter drives did. The first WD 2TB Blacks and the first WD 2TB Greens did have issues - but all of my 3-platter 2TB Greens are still going strong, so that seems to be the sweet spot.
1-3 platters seems to be best
. Beyond that, your odds of mechanical failure go up too much. A single platter drive is definitely the most reliable, so long as they don't skimp in other areas. I wonder how long those single-platter single-side 320GB Samsung F4's are going to last?
Anyway, sequential speeds are mainly determined by platter density. (And also what the head/controller are capable of.) As density increases, it does get harder to lock onto a track - that's why the highest densities are usually used for Green drives, and the next highest densities are reserved for high end 7200RPM drives. One company (Hitachi) does like to use super high densities on all their drives - that's why most of theirs have max sequential speeds in the 150-200MB/sec range, but also have 16-17ms access times to match. (even on their 7200RPM drives) Western Digital on the other hand prefers to cap sequential performance. You get much less jaggy HDTune graphs on most WD drives. Some (like the 5400RPM WD20EARX) get close to 15ms access times, which is superior to Hitachi's 7200RPM drives. (except the sequential performance caps out at 120MB/sec - far far lower)
Anyway, that's enough rambling for today.