Most Laptops have 5400. Thats because these consume less power.
Only some High performance laptops have 7200.
For some time now Apple has stopped using 7200rpm drives as their high performance option. They've gone to solid state flash drives. I think the reason has that (1) 7200rpm drives don't offer much more in terms of performance and (2) the 7200rpm drive uses more battery power
Sometimes spinning the drive faster does nothing at all. What really matters is the rate at which the bits fly under the read/write heads. This is determined more by the number of bits in one circular track then the length of time it takes to make one revolution. 5400 and 7200 are not very far apart, you get only a 50% gain going to 7200 but if the number of bits can by increased by a factor of 5, you have a 5X speed advantage. In recent years speed has been driven by increasing bit density. Like I said above Apple's found that 7200 RPM is just not worth it and figures that SSD is the better option. I have to agree, you can get a SSD drive now for $200 that will hold Ivory and many other virtual pianos.
All that said, sampers lke Ivory really don't need a fast disk drive, The amount of audio data read is not great. What helps more is lots of RAM
If you are buying computer gear for music you might also want think about noise. A spinning disk can make noise and if it is also mmaking heat may cause a cooling fan to run. SSD wins over any disk in terms of noise.
