Cache sizes have not seen gains proportional to RAM or HDs.
My 486 built in 1993 had 8 KB cache, 4 MB RAM, and a 120 MB HD.
My desktop built in 2009 has 2 MB cache, 2 GB RAM, and a 250 GB HD.
Okay, the cache has lagged behind by one or three doublings compared to the other storage types. But that's still pretty close to proportional in a world of exponential gains.
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.
http://seven-degrees-of-freedom.blogspot.com/2009/10/latency...
That "2 MB" is either L2 or L3, which your 486 didn't have.
The L1 on your desktop is not much larger than the only cache that your 486 had.
As frequency increases, the length of the path that a signal can travel in one clock decreases. Fortunately, cycle-time increases have been accompanied by transistor size decreases, so the net result is that L1 sizes have been roughly constant.