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If a computer has two different physical internal hard-drives, whether a desktop, or a laptop that has a primary hard-disk and another internal drive connected say in place of the CDROM, would it be faster to read and then write from one drive to the other, or do read/writes to within the same drive achieve the same speed.

This question arises because I often need to re-rip (convert) a large multimedia file (>4GB) from one format to another, where the file is often demuxed into video and audio and then remux'ed into a single multimedia file. Preferences could be set such that the demuxed files reside on (and are read from) one drive and muxed (written) onto another drive.

What if I am using a second drive that is USB 3.0 and I have SATA 1.5? SATA 3.0?

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migrated from serverfault.com Jul 20 '12 at 2:09

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Harddrives don't have independent read and write capacities, so it would be faster to read from one drive and write to another as opposed to reading and writing to and from the same drive. There will probably also be a speed increase due to the reads and writes being more sequential. This is assuming that the operation is IO bound however.

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Yeah, my experience with video converting is that the process bottlenecks at the CPU, and boosting disk I/O doesn't do anything at all. (Also sounds like a help-me-rip-my-DVDs-faster question, but whatever.) –  HopelessN00b Jul 19 '12 at 20:11
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@HopelessN00b Yes, actually encoding video will be CPU bound. Converting container formats or ripping without re-encoding the video would be IO bound however. –  mgorven Jul 19 '12 at 20:17
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