The Ti4800SE is a Ti4400 with 8x AGP
The Ti4800 is a Ti4600 with 8x AGP
Both are usually a little better than an FX 5600 with Antialiassing or ansio disabled; both are usually a little worse than a FX 5600 with AA or ansio enabled.
It comes down to cost and what you're looking for.
If you absolutely want DirectX 9 and you use AA & Ansio, get the FX 5600.
If you never use AA & ansio, and don't plan to, save the money and go with the 4800. Chances are it's alot cheaper.
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Radeon 9500 w/256 bit memory bus @ 367/310
AMD AthlonXP 2000+
3dMark03: 3439