A little Mysql cache seems to go far

I made a post to enable mysql cache with mysql 4 (which is not enabled by default) and was sucseful in doing so with the help of the community. Here is the post :
http://forums.contribs.org/index.php?topic=26575.msg108622#msg108622

Upon doing this I was able to monitor the results with cacti and I believe they may be signifigant to a high usage sight. If you look at the mysql related graphs in the "week" periods you can see the difference
http://ericswww.com/cacti/graph_view.php?action=preview?action=tree&tree_id=1&leaf_id=7&select_first=true

I don't have enough knowledge of the inner workings but it appears that as little as 1meg cache shows a big change in the usage.