I mentioned a few weeks back that I had ordered a larger hard disk that used a very large cache to get some of the benefits of SSD drives. And as some of the reviews pointed out, performance of a large cache disk drive improves over a period of days or more, as it learns which are the most commonly used parts of the actual hard disk, and leaves those preloaded in the cache.
The other big improvement was purchasing AVG PC Tuneup. There is no question in my mind that it cleaned up a lot of broken stuff in terms of registry entries and unused components. This six-year-old dual core laptop now screams!
UPDATE: Dragon Naturally Speaking can't tell "cash" from "cache." Fixed it. They are, of course, roughly equivalent at current prices.