# Hard Drive: 5400 RPM versus 7200 RPM



## monokitty (Jan 26, 2002)

I was told that under Mac OS X, a 7200 RPM drive is much faster than a 5400 RPM drive. I know that for a fact, however; is it worth replacing my 5400 RPM drive (20 GB) for a 7200 RPM drive? I'm thinking of getting a 60 GB 7200 RPM drive (100/ATA-based). Thoughts?


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## MacDoc (Nov 3, 2001)

RPM is mostly meaningless when it comes to throughput these days - it has only a minor affect on latency so if you were looking up many records in a Visa database the rpm might make a difference.
The real factors are data density - how much in how small a space and cache size.
Typically 5400 rpm drives also have small caches to keep the costs down.
Western Digitals running at 7200 with 8 meg caches blow the doors off other 7200 rpm drives with 2 meg caches.
Current 7200 rpm drives move 3-4 times the data that expensive 7200 and 10,000 rpm scsi drives of a couple years ago - why? because more data is crammed into a smaller area so more is read faster - not because the rpm has gone up but because the head has less distance to travel. Couple that with bigger caches and the throughput speed climbs withoput any increase in RPM.
The 160 drives at 5400 rpm with 2 meg caches have very similar throughputs to the smaller drives at 7200 rpm because they have higher data densities.
Right now Western Digitals with 8 meg caches and 3 year warranties are simply the best buy out there. Only slightly more expensive than the competition with 1 year warranties and smaller caches these are highly recommended especially for start up drives that you run on - really makes a difference to perceived performance and excellent for graphics where scratch speed is important.
Yes a set of 4 15k scsi drives with 16 meg caches RAIDed on a dual 160 card can also blow the doors off ANY IDE, RAIDed or not but the price is very very high.


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