[svlla]

Good point :)

Here's a different take, then, and probably harder to verify, but I am guessing is true:

Cache utilization has increased much more than RAM or HD, not just because programs are handling more data but also because of increases in program size and number of programs being run simultaneously.

Your hard drive is probably not full... RAM could be, depends on your workload... but I bet most caches are churning like mad, more than they used to be.