CPU Hardware ADD-ON

I've somehow or rather heard and saw about AMD processors being physically upgraded by adding attaching another hardware device in between the processor and the socket.. which gives better performance.. is there any such hardware??

There is no such device. Well, there is something like that, but it just allows multiplier selection with jumbers for boards that don't support changing the multi. THere are also some people who do some mods with wires in the sockets, I think you can do the L5 mod to make an athlon-XP work in SMP that way.