So far I've only compared them side by side only powered, and then I connected them to my comp and ran Hitachi's AAM test to compare again.
Test done with the drives sitting on carpet, powered by a PS with it's fan off, in a room with nothing on, and in a quiet house and quiet neighbourhood with nonexistant traffic.
Verdict: Seagate wins. Samsung' light whine is higher in pitch, and it's possible a tad louder.
Test done inside my case, ear about 5 inches away from the drive. Drive's sitting on 1inch of foam forming a "basket" for the drive. Only fan runnning was an aluminum Evercool single bearing 92mm fan @ 5v, which is actually not silent at all. Used Hitachi's AAM Test to create seek noises, left at lowest setting (128 for both drives).
Verdict: Samsung wins. It's noise seemed to be a bit more muted and blended in better with it's idle noise.
I still have to test the drives head to head when I install windows on the Samsung and compare noise during bootup and otherwise.
OVERALL, the drives are pretty similar in terms of noise, and for now, I'd give the Samsung the slight edge. My testing, however, still isn't completed and I won't be able to truly say which drives wins until I finish. I will post back in this thread when I do finish.
AMD64 Venice XP3000, Retail HSF, Asus A8N-E, 2x512 mb Samsung TCCC PC3200 @ 400mhz, 200gb and 250gb WD SE SATA's, Sapphire X600 256mb Pro, Pioneer DVR-107D, LG 16x DVD, Zalman ZM400B-APS, Inwin q500n.