RPM for external hard drives...does it matter?

ShadowTiger

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Apr 19, 2010
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Hi,

I have what may be a dumb question...does the RPM for an external hard drive matter?

I just tested an Hitachi 80GB SATA-II 7200RPM hard disk with USB 2.0 and then with eSATA (everything else the same). HDTune tells me this:

eSATA:
Transfer Rate: Starts at around 60 MB/s and slowly tapers off to around 30 MB/s
Access Time: 14.4ms
Burst Rate: 148 MB/s
File Benchmark tops off around 40 MB/s read and 33 MB/s write.

USB 2.0:
Transfer Rate: 33 MB/s (pretty much a flat line)
Access Time: 14.6ms
Burst Rate: 33.3 MB/s
File Benchmark tops off around 38 MB/s read and 25 MB/s write.

(So first off, except for the burst rate, I wasn't as impressed with eSATA as I thought I would be.)

Okay, my thought is that especially for USB 2.0, but even for eSATA in this case, it seems like if I got a 5400 RPM hard drive I don't really think I'd see much difference (as the connection would be the bottleneck). Am I wrong in this? What do you think?

Thanks!
Peter