well i dont no what that link is about and i wouldnt do it there is no point soldering anything on a grahics card or any other peice of electronic equipment its not worth it they are easily damadged if you dont no what you are doing. and if you do accedently solder the wrong thing or fry one of the chips then your stuffed and you might aswell throw the card away, but
the reason why many people talk about radeon 9500 and 9550's is because the 9550 runs the same core as the 9800
so the core can be overclocked by a fair bit ive got mine from stock 250 to 370 and the memory from 200 to 270, the GPU was fine not hot at all but the memory almost burnt my hand when i touched it lol.
the 9550 can also be modified by flashing a new bios to them you can go from a 9550 to a 9800 without paying for it.
softmod drivers are fine to use i used this onehttp://www.techpower...d/downloads.php
it has done me well i have noticed a frame rate increase of around 7-10 frames per second average
there are also omega drivers
they can be found here:http://www.omegadrivers.net/
i havent yet used omega drivers but i have heard about them most people say they are fine
but i would try the first link first as i dont no what the omega drivers are like