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?"
Windows Gaming Box: AsRock Z77E-ITX / i5-3570k @ 4GHz / 8GB RAM / GTX 660Ti / Samsung EVO 250GB / Seagate Momentus 750GB / Silverstone SG05.
NAS: Foxconn D-70S-P (Celeron 1037U) / 4GB DDR3 / 4x Toshiba DT01ACA200, 1x DT01ACA300, 1x DT01ABA200, / Fractal Node 804.
Last edited by dave_the_nerd; 11-07-2012 at 12:26 PM.