I have Dell E520 Core 2, 2GB, 250GB HDD (Samsung SP2504C). I bought it around 5 months ago. I was using an old PC before this which was very noisy but I did notice hard disk noise on my new PC especially when PC was booting and when I'm loading some application. Them somone else who bought the same PC reported the same crunchy sounds. I read that this samsung is really quiet. Does it mean you don't hear anything at all, but I do hear.
Also in the BIOS it has different options for HD, Quiet, Performance, By Pass etc. but it does't make any difference in noise reduction. I think i'ts the motherboard which doesn't support noise reduction option, but I'm not sure. Is there software with which I can check the noise level?
Some Samsungs are still noisy - even with their quiet reputation. Try Feature Tool to enable the AAM (advanced acoustic mode) features, it can be downloaded from Hitachi's website. And don't worry, it works on Samsung drives as well as Hitachi's.