Depends on the drive. You get a not-quite-doubling of sequential I/O performance. Latency is about the same though. Just saying "Seagate" isn't super helpful, since they have oodles of different-performing drives.
Might be a good place to start if you're trying to find the numbers for a specific model.
Many types of non-pro (Intel ICH or Software) RAID controllers will circumvent/work around the absence of TLER. I'd probably do that - the random/seek performance of the WD drives looks like it would be noticeably better.
Scientific progress goes "Boink?"
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Last edited by dave_the_nerd; 11-07-2012 at 12:26 PM.