There is a diffrence in write and read speed, but all desktop drives are 7200 these days. On laptops, I would suggest trying to get a good HD, because it will help increase boot speed and you will notice a diffrence when your doing HD intensive appliactions.
Sure, there is a difference. The numbers aren't there for fun, they do serve a purpose. The greatest difference for me is using a SATA 36GB WD Raptor (ATA150, 15K RPM) vs. a standard PATA 7.2K drive. Windows XP installs in around 15 minutes on the Raptor, around 40 minutes on the standard PATA.
Windows also boots up faster.
You will not notice a difference if you are only accessing Word documents or such from the slower drive. I store all my intensive programs on my Raptor (C:\) and use my larger PATA drives for storage. There is no noticable slow-down accessing a file from one drive over the other.
Verry true... and most of the laptops have 5400 rpm until now where u get 7200 but they are pretty expensive ... so its a trade-off as usual .
Now the new harddrives are 10,000rpm so they will be much faster !
I'm sure you have gotten the point on performance by now. If you would like to see an example of the speed difference, and have access to such parts, install a 7200RPM+ drive with an OS, and then install a 5400RPM for storage. create and delete a file from the 5400 drive, you may not notice a difference... but watch what happens when you try to empty your recyling bin... did you stall yet? yes, i've had my computer stall for as much as 2-3min depending on the size of the files being deleted. This is a minor example, but it very quickly shows the performance boost on the faster drives.
The hard drive that spins faster is going to have better speeds, and I'm sure you get this by now...
However I wanted to point out that the speed the platter spins at is not the only things that matters, things such as the transfer rate (like IDE and ATA) and buffer size also play a major role. For example you can have a hard drive with a 5400 RPM and 16 MB buffer and a 7200 RPM with 2 mb buffer. So if it is something like this the gap between the difference of speed will be less... you will notice a big difference, but not all that much.
Apart from speed, I think the sound is different as well, because my friends laptop (which has a 5400 RPM drive) sounds different than my pc (7200 RPM).
That's right. There are several things to take into consideration to measure disk speed. Interfase (ATA, SATA, SCSI), Buffer (2 Mb, 8, 16) and RPM. I used to have 2 of those Raptors on RAID 0 and I can assure you they were incredibly fast. Pity they generate too much heat and one of them burnt.