You can certainly beat it in terms of supported functions. Since it only supports direct X 8.1 functions or lower, the rendering quality will suffer on newer games. I bought a refurbished 9500pro for $130 about a month back, and 9600xt's can be bought refurbished for the same price (or less).
In terms of raw speed in DX 8 games, the 4600 is generally a little faster. However, in newer games that impliment shaders to a higher degree, this is not the case (and will become less and less of the case).
Also, Newegg is selling refurbished 9700pro's for as low as $150 now, which are significantly faster cards. I don't know if your comfortable buying refurbed products though. If not, thats totally understandable. If you are however, $20 more will be totally worth it.
Read this article though:
Linky
It pretty much shows even the 9600xt to be a supperior product, and you get full DX 9 support. Order of preference for gaming (IMO obviously): 9700pro, 9500pro, 9600xt, TI 4600.
Of course, if your buying that card just to mess around with it, it will serve your purposes. Lemme know what you think.