How Fast Are Your Hard Drives?
March 17th, 2009
According to the interface specifications, all of my hard drives should be running at about 160MB/s. After using the HD_Speed utility, however, I found that actual, sustained transmission times are a fraction of the theoretical maximum. While this wasn’t a huge revelation, I was surprised to find a drive running at one-third the speed of the others.
Link: http://www.steelbytes.com/…
(via Lifehacker)
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[link]josh Says:
March 17th, 2009 at 9:13 am
Ignoring reading from/writing to the drive cache, drives don’t sustain more than about 100MB/s these days. [ http://www.hardwaresecrets.com/article/567/3,
http://www.seagate.com/docs/pdf/datasheet/disc/ds_barracuda_7200_11.pdf ]. If you really want fast, use SSD drives. For example, Pure Silicon Nitro reports sustained rates of 240MB/s and 215MB/s for reads and writes respectively. Of course your budget will suffer ;-) Plus “no” seek times since there are no moving parts.
The limiting factors on a drive with rotating parts are seek time and data density [bits/inch of track]. The faster you spin, the quicker you can get to data and the more bits fly under the head. About 5 years ago we liked some 10,000 RPM drives [ http://techreport.com/articles.x/6390 ] and got about 30MB/s sustained rates per drive. However, we couldn’t get more than about 100MB/s using RAID drives before other factors [CPU speeds, driver limitations, bus speeds, etc.] started to limit throughput. These days I’ve seen claims of drives being able to transfer information ( from cache) as fast as the interface will take it and because data densities are so much greater, sustain speeds of 100MB/s using just 7,200 RPM drives. Cheaper faster better. Yay!