Video card for civ iv

[LIONFURY]

Hello

I just bought civ iv complete and it runs at 5 fps.

My system:
Windows Vista
1.6 ghz Celeron CPU
2gb ram
Intel 82945g Express Chipset family.

Obviously its the video card that is slwing me down the most. So my question is, which of the following 2 video cards would be able to run civ iv best (preferably 20+ fps)

Radeon HD 6450 1 gb ddr3
Geforce 8400 GS 1 gb ddr3

Thank you!

 

[kiwitt]

I run a HD 4870 and it runs well.

 

[Matty R]

OS: Windows 7 Ultimate 64-bit
CPU: AMD Phenom II X2 555 @ ~3.2GHz
Mobo: Gigabyte GA-MA78LMT-U52H
RAM: (2x) 2GB Hynix Single-Channel DDR3 @ 535MHz
GPU: Sapphire Radeon HD5670 512MB DDR5

Civ 4 runs brilliantly with these specs, even late-game when the world is awash with idle units.