Things to keep in mind while editing Mysql "my.cnf" file
There are a lot of inter-dependencies.  Casual use of the Query cache can speed up some queries.  Busy systems tend to be slowed down by the QC.

Overcommitting RAM is deadly for performance.  Here is a discussion of that, and some of the settings.

32bit system with 8GB of RAM ! -- Is that a 32-bit OS?  Or a 32-bit MySQL on a 64-bit OS?  If the former, then 4GB is totally idle.  In either case, MySQL is constrained as if it has only 4GB.

What kinds of things slowed down when you changed what settings?  We can probably explain what happened if you give us some details.