[anamax]

> My 486 built in 1993 had 8 KB cache, > My desktop built in 2009 has 2 MB cache

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.