Drive RPM

D

DoubleZedRed

Gawd
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Jan 12, 2009
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I was discussing upgrade options with a friend of mine who's looking to upgrade from his current hard drive (an old maxtor 7200) and i suggested that he get two new 7200's and run them in raid0. he had mentioned that a friend of his said that a 10,000 rpm drive would be faster than 2 7200's in raid. is that true? and what effect does platter speed have on overall drive performance?
 
Increased RPM usually helps the more important seek times however. With that said I swear my 5400 RPM 2TB WDC green seeks faster than my 750GB Seagate 7200.10.
 
drescherjm: it does not seek faster throughout the entire disk surface; it just has more bits so a 20GB windows partition is 'closer' physically (less tracks) on a 2TB drive than on a 750GB drive with 250GB platters. HDTune Pro can show you this with the random access benchmark.

Faster RPM does mean faster STR, but increasing data density is far easier to improve STR, as increasing the rpm is very problematic (heat, friction, wear, power consumption).

But 5400rpm 2TB disks usually are faster than 7200rpm 160-250GB per platter disks.
 
I have all drives on linux. The performance difference was seen when running a windows VM under the linux host (using vmware server, kvm and virtual box) and inside that windows VM building large applications. For me I have over 2 million source code lines in my last two researech projects if I include the 4 to 5 opensource projects I use.

EDIT: When I think of it I think I know why. Arial density. The 100GB file that that was used for the VM virtual buid disk would be on less tracks of the 2TB since the 2TB has 2 times the arial density of the 750GB. 500GB platters versus 250GB.
 
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Yes. :)

So that's why higher platter density, translating to higher areal density, is ultimately smarter than having higher rpm. We could increase density many times still, but increasing the rpm is not attractive at all due to heat generation even when doing nothing.

Though theoretically we could see dynamic rpm drives in the future to remedy that problem, the target group for high rpm always was power users and business. Business will be looking at SSDs for performance instead, with high rpm drives only being useful in an excessively write heavy environment where todays SSDs do not have enough endurance; the replacement costs would cause the total cost of ownership to go skyroof.
 
In terms of your friend's upgrade, here's my thoughts in order of preference that don't break the bank:

1. SSD, something like an 80gb Intel X25-M g2 ($220)
2. 2x Intel 40gb X25-V in RAID 0 ($235) + old drive for an image of the RAID 0
3. 500gb Seagate Momentus XT hybrid drive ($130)
4. 1x Intel 40gb X25-V + old drive for data ($118)
5. 300gb/600gb Velociraptor ($240/$280)
6. 2x 7200rpm drives in RAID 0 (plus backup)
 
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