Texture Loading

I was wondering what controls the texture loading in front of the A/C. I don't mean the brown or blue squares, but the refresh of the scenery as you fly. Is there a setting in the FS9 cfg, or is it slider controlled. I have lowered the sliders, and it didn't make any difference. What is happening is I am seeing chunks of scenery ahead start blurry and then all of a sudden abruptly become clear. There is no smooth transition. It is like you are looking through a camera lens, and manually focussing. My sight distance is 60 mi, and I have also played around with that, and it didnt make any difference. I have the settings in the FS9 cfg set to the optimum ones to reduce blurries. I have no problems with the scenery immediately in front, it is clear and sharp, it is the mid range scenery that is the problem.I have an athlon 64 3400+ cpu, overclocked to 2.4, an ATI X800xl 256 mb video card, and 1 gb of high quality OCZ ram. Any help or opinions would be greatly appreciated.Thanks,Bill