Yep, the 4600 is a much better/faster card than the 5200FX.
Not many places I put any faith in when it comes to video card reviews. Many are very biased. But, if you can glean through the bias over a few sites, then you might be able to figure out what is good and/or bad.
Just FYI humble, NVidia and ATI are both set to release new high end cards in a month or two, so prices of current products should drop after that.