Here are my specs:
AMD Athlon 64 X2 6000+
2 GB RAM
Geforce 8400 GS
CODEGEN 450W PSU
So I'm looking for the best video card i can get under $200 without bottlenecking my GPU. My motherboard only has a PCI x16 slot so I'm looking at getting a Nvidia card since they use PCIe 2.0 instead of PCIe 2.1 which I have heard can be incompatible. I'm also looking at upgrading the power supply to some kind of Antec efficent 450W supply.
I think my best option at the moment would be the Geforce 550 ti but I'm afraid it might bottleneck http://www.newegg.com/Product/Product.aspx?Item=N82E168...
From what I know it will be bottlenecked. And I see two options:
1st option: Buy a 450/550 and a couple more ram so you will have at least 4GB (I know that you have XP and possible 32 bit but we want at least to cap this). cost: around $150.
2nd option: Keep your money and wait a bit till you could spend around $300-400.
Then you could buy an ivybridge cpu (i3 for around $110), a new mobo (H67 or similar for around $80), 8GB RAM (around $40) and for around $150 a new gpu (maybe HD6850/GTX460) they should cost around $350-$400