What's the difference between a 6.0Gb/s and 3.0Gb/s HDD?

[xenonn]

Is there a major difference between a HDD that says 1TB 7200 RPM SATA Hard Drive 6.0 Gb/s and the other that says 1TB SATA 3.0Gb/s Hard Drive?

What's that 6.0Gb/s and that 3.0Gb/s? Do they make a huge difference? Can I assume that both HDD runs at 7200 RPM since the second one didn't state its RPM speed?

Is it true that only specific mainboards can support the 6.0Gb/s HDD?

 

[Azn Cracker]

no difference. thats just the maximum theoretical bandwidth for the hard drive. One HDD is SATA 2.0 and the other is SATA 3.0.

Hard drives dont use that much bandwidth so it wont really matter.

It might matter on SSD's though

 

[Cons29]

that is sata2 and sata3, but note that this is theoretical speed, and being mechanical drives they would never be that fast. there wont be any perceivable difference between the 2 whether sata2 or 3.
but if we are talking about ssd then it is a different thing. as a sata3 ssd can saturate sata2 bandwidth, those are of course numbers and between ssd's it will be difficult to notice the difference.

but between ssd and mechanical hdd the difference is huge. just to give an example, i have an old sata2 ssd (not even the fastest at that time) and my boot time is 18sec

 

[Paperdoc]

Cons29 has the heart of the matter. Two additional notes.

A SATA 6 Gb/s drive CAN work just fine on a SATA 3 Gb/s port - they are backwards compatible. So don't worry about whether it can work in your machine.

The 3 Gb/s drive you cite did not specify a rotational speed? Do NOT assume it also is 7200 - find out! It could be any of several speeds. Also check out the drive's cache size. A cache of 8MB is too small, 16 MB usually is small, 32 MB is quite all right, and 64 MB is marginally better. Some energy-saving drives use a slower rotation rate of 5400 rps, and a higher cache size of 64 MB to help offset the slightly slower performance from rotational speed.

Of two drives with identical rotational speeds and cache sizes, a SATA 6 Gb/s unit MAY be only slightly faster than a 3 Gb/s unit, or there may be no difference at all.