Have you tried turning fastwrites back on? Im sure i read on these forums that fastwrites turned off is the cause of the pausing problems. Try it and see what happens!
What is your AGP Aperture size set at? Recommended is 256
You have 1GB of ram so try turning off your pageing file (no pageing file) or try it on system managed size.
Ive set my pageing file size to no pageing file and my 5900 Ultra runs far cry without pauses but i had to set it to system managed size to play doom3 on ultra (bad framerate tho) and MOH pacific assault demo but far cry seems to be jerkyier now??
Maybe these will help you