nVidia Geforce GTX 295 problems
I can't offer any advice on this card specifically but my experience of Nvidia drivers in general is that they take several generations before they become one hundred percent reliable on new cards.
I'm running dual 9800GTX+'s and it took about six months before Nvidia released a set of drivers that let me run the game at max framerate. Up until that point I was using drivers that were several generations older than the latest ones. Every time they released a new set I installed them, ran CoX, saw a drop in performance and rolled back to the previous set.
All I can advise is experimenting with previous versions of the drivers to see if any of them give you performance enhancements (I know, counter-intuitive but it worked for me).
Of-course I'm assuming there are earlier drivers for that card! It's quite new....
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You're running a Pentium 4 3Ghz with the fastest card currently available? I hate to say it but your CPu is holding your system back really badly. If you were to get that changed then you'd certainly notice an increase in frame rate in quite a few games I'm sure.
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@Miss Chief
I finally bought this card and have it running on my computer.

Unfortunately, it seems to not be functioning properly as I can't have any of the following options turned on, without the framerate dropping to 3: FSAA, Depth of Field Effects, Bloom Effects and Desaturation Effects. They also make the game behave like a strobe light...
Funny thing is, this seems to be a CoX problem only as I have tried running Fallout3 on maximum options and it runs smoothly.
Anyone out there with some input that can help me?
For the more technically inclined here's a DxDiag excerpt:
Operating System: Windows XP Professional (5.1, Build 2600) Service Pack 3 (2600.xpsp_sp3_gdr.080814-1236)
Language: English (Regional Setting: Portuguese)
System Manufacturer: INTEL_
System Model: D975XBX_
BIOS: Default System BIOS
Processor: Intel(R) Pentium(R) D CPU 3.00GHz (2 CPUs)
Memory: 2046MB RAM
Page File: 999MB used, 4971MB available
Windows Dir: C:\WINDOWS
DirectX Version: DirectX 9.0c (4.09.0000.0904)
DX Setup Parameters: Not found
DxDiag Version: 5.03.2600.5512 32bit Unicode
Card name: NVIDIA GeForce GTX 295
Manufacturer: NVIDIA
Chip type: GeForce GTX 295
DAC type: Integrated RAMDAC
Display Memory: 896.0 MB
Current Mode: 1680 x 1050 (32 bit) (60Hz)
Monitor: SyncMaster T220HD(Digital)
Monitor Max Res: 1680,1050
Driver Name: nv4_disp.dll
Driver Version: 6.14.0011.8122 (English)
DDI Version: 9 (or higher)
Driver Attributes: Final Retail
Driver Date/Size: 1/15/2009 08:19:00, 6168960 bytes
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