Trouble With Nvidia Graphics Card.Follow

So I just updated from a Radeon 9250 256mb PCI to a Geforce 8400 512mb PCI. It seems, however, that I've lost FPS in major cities and BGs. At first I thought it was that the 8400 was maybe an older model, but that doesn't make sense. At the moment I'm downloading the Nvidia Omega Drivers to see how that helps. Did I downgrade, or is it something I can fix? Just tell me what info you need and I'll provide. Let's start with this:

------------------
System Information
------------------
Time of this report: 12/23/2008, 17:29:00
Machine name: MEALSTROM
Operating System: Windows XP Home Edition (5.1, Build 2600) Service Pack 3 (2600.xpsp_sp3_gdr.080814-1236)
Language: English (Regional Setting: English)
System Manufacturer: Dell Computer Corporation
System Model: Dimension 2400
BIOS: Phoenix ROM BIOS PLUS Version 1.10 A05
Processor: Intel(R) Pentium(R) 4 CPU 2.66GHz
Memory: 2046MB RAM
Page File: 232MB used, 1855MB available
Windows Dir: C:\WINDOWS
DirectX Version: DirectX 9.0c (4.09.0000.0904)
DX Setup Parameters: Unknown Switch (6)
DxDiag Version: 5.03.2600.5512 32bit Unicode


Edited, Dec 23rd 2008 5:57pm by LiptonSoup

I downgraded. Oh well. I guess I'll just give it to my mom for xmas. lol