I just installed a new 1 TB drive into my MacBook tonight in the optical bay and figured I'd share the results since the drive I installed is brand new...so new I was the first to buy one from the store last night!

The drive in question is the new Hitachi 1TB Travelstar 5K1000 (http://www.memoryexpress.com/Products/MX39203) which is currently $119 at MemoryExpress. What makes this drive unique is that it is a SATA III drive that does negotiate at 6 GB/s in our MacBooks. The drive is also pretty thin so it has no problems being installed in our machines.

So how fast is it? Well I ran BlackMagic's bench test and got the following results for my OCZ Agility 3 SSD, original Apple Hitachi 320 drive and the new 5K1000.

Drive / Write / Read
OCZ / 110 / 170
320 / 60 / 61
1TB / 97 / 97

To me that's pretty damn respectable for a platter drive.

I was unaware that there was a 1TB drive that was small enough to meet the Mac's demanding 9.5mm criteria. Thanks!

I just removed one out of my MBP and replaced it with an SSD.

I was unaware that there was a 1TB drive that was small enough to meet the Mac's demanding 9.5mm criteria. Thanks!

A)Wd has made one for close to a year now
B)9.5mm isn't a "demanding Mac criteria" it's the standard height for 2.5" drives
C)All late model mac laptops (post late 08) can accept non-standard 12.5mm drives, like the first generation 1tb 2.5" drives

Yup, Apple certainly isn't the only manufacturer to have a 9.5mm limitation. I don't see it as a bad thing, all the hard drive manufacturers have found way to squeeze more storage into these 2.5" 9.5mm drives, and because they're produced in mass capacity they cost just as much as the 12.5mm equivalents if not less.

The impact for our household is that I can now take ownership of our extensive iTunes library. Previously it had to reside on the family iMac as non of the laptops had the drive capacity to host it...yet I did all the maintenance of the library from my laptop. When I benchmarked the 1TB drive in the iMac (a decent Samsung) it was actually slower then the drive in my Macbook which surprised me as I expected the larger drive to out perform it. We really are moving to the point where we can get excellent performance in a laptop and not have to give up capacity to get there.

Wow, despite being a 5400RPM hard drive too. Maybe it's time get a WD Caviar Black drive for your iMac... ;)

I'm pretty sure I'm going to drop a solid state drive into the iMac. It won't need much capacity once I finish transferring iPhoto and iTunes but will benefit a lot from a SSD. I've already maxed the ram and it still beach balls a fair bit...esp with multiple users all logged in etc.

The speed of a hard drive isn't just its rotational speed, it is the areal density as well.
Manufacturers can make thin 1 TB drives because they can now pack 500 GB on a single 2.5" platter, as opposed to last years state of the art of 320 GB -- which required stacking three platters for 1 TB, and thus the 12 mm thickness.

With a 500 GB platter the data density is 166% higher than before, so 166% more data goes under the heads in one revolution of the disk. One revolution in 1/5400 sec vs 1/7200 sec is a factor .75 -- 166 * .75 = 124.5

So with the areal density increase, the new 5400 RPM drive should still be capable of 24% more throughput off the platters than a 7200 RPM 320 GB platter drive, given that both are the same size (2.5").

This is downgraded a bit by higher rotational latency on the 5400 -- the amount of time the head has to wait once it is position before the desired sector swings around to pass under it -- on average 1/10800th (0.000092) of a second at 5400 RPM vs 1/14400th (0.000069) of a second on the 7200 RPM.
The head seek time and rotational latency are relatively more important for small random reads and writes (which is one reason SSDs are faster in the real world, because they have no seek or latency time). The maximum throughput is more significant with large file reads and writes.

A 3.5" drive has a throughput advantage over a 2.5" drive simply because of the larger diameter platters. The 3.5" has a much longer perimeter, and so more data can pass under the heads per rotation at least on the outer tracks.
But if the 3.5" drive is half full, and the measurement is done on inner tracks of the drive, then the advantage is lost. So its not unusual that a 500 GB platter 2.5" drive can outperform a 320 GB half-full 3.5" drive.

But if the 3.5" drive is half full, and the measurement is done on inner tracks of the drive, then the advantage is lost. So its not unusual that a 500 GB platter 2.5" drive can outperform a 320 GB half-full 3.5" drive.

To what extent would cache size affect this?

Cache size only impacts small files not sustained at all. As CR mentioned, data density is very important - rotation affects how fast the head can find something and to a degree the sustained.

The XT series from Seagate have very large caches up to 8 GB that use intelligent optimization to keep you most used data in the SSD portion.
It's not a bad trade off and has been in the Intel motherboard for a while - only Seagate has used it so far.

It improves start up times and day to day common use - it does not improved sustained.