The above post is right, there is no difference in performance between the K6-3 and the k6-3+. The difference lies in the core shrink ( .25 to .18) this allowed the k6-3+ to run at lower voltage and consume less power making it feasable to run it in a notebook machine, this is why you will not see many k6-3 vs k6-3+ test do to the fact they are virtually the same. Due to the core shrink and increased effecincy the + series is alot more overclocker freindly however. The only problem is that your motherboards bios needs to support the + to use it.
A little bit of knowledge is a dangerous thing!