HD3650 GDDR3 will edge out the 9700 Pro some. 9700 Pro is around 19 GB/s memory bandwidth, and HD3650 GDDR3 around 25 GB/s, not much difference. Keep in mind this is directx 10.1 vs directx 9.0 especially if gaming in XP with games that is fussy. Also pixel per second is not that much also 9700 pro is 2.6 GP/s versus HD3650 2.9 GP/s.
Honestly, should had gotten x1800 or x1900 and easier to find in AGP favor and powerful 9.0c GPU, and HD3850 or HD3870 in PCIe is so inexpensive but they are directx 10.1
Checked the ebay and i find lack of AGP cards within your budget would push me to switch out the motherboard for PCIe with socket 939 motherboard and pick up, easy to get x1900 t0 keep with 9.0c support for XP. XP never had ventured beyond 9.0c. Well chosen socket 939 with PCle motherboard should not be that expensive.
When back in the day, I was not aware how hobbled the HD3650 were and the performance was only twice of what low end HD3000 series was, should had saved up some more and got PCIe HD3850 instead. Was because I was upgrading from Geforce2 MX and was still disappointed back in the day. Live and learn.
High end video card pushes out AA better vs low end would at any resolution.
Great Northern aka Canada.