Yeah, 5400RPM would technically be fast enough for a lot of setups....but I would never recommend one. If you just recently got it, can you take it back? 7200RPM drives are not that much more expensive, and the extra speed all but removes the potential hard drive bottleneck for typical multitrack audio.
Chris is right, it has more to do with the processor and chipset and the rest of the devices in the machine than how fast the hard drive spins.
I just did some numbers for a different thread. Technically, a 5400RPM drive that can sustain 12MB/sec transfer rates (I'm not sure what the norm is for 5400 anymore), can do 41 24/96 tracks. Now that's only a theoretical maximum. In real life, when dealing with multiple large files there are a lot of variables to factor in, so it might be safe to halve that number which leaves you with a very conservative estimate of 20 tracks. Jumping to a 7200RPM drive, which will typically sustain in the 25MB/sec range, takes the mathematical 24/96 limit up to 86 tracks. Even if you only got half of that in a real world application, that's still 43 tracks. Don't take ANY of this to heart though, as each case must be looked at seperately. Also, if you simply record at 24/44, you technically double the maximum number of tracks the drive can sustain, and in our "conservative" estimates above, that means over 40 tracks at 5400RPM and over 80 tracks at 7200RPM.
The point: buy 7200RPM to play it safe. It's not much more money. A 30GB Maxtor 7200RPM drive can be found on the net for $75. A 5400 drive should technically work, however, unless you expect a massive amount of tracks. As chris mentioned, in most cases the rest of the system will come up short well before the hard drive itself.
Slackmaster 2000
