[color=#000000]It's VERY difficult to max-out
FS9 on your system,
SSI01. Before the PC in the signature I had an Athlon XP 2400 with only 1 GB ram and a Gefo 6600GT 128MB and never had texture problems. The sim slowed down only when too many AI planes loitered around... only.
What kind of Nvidia video card do you have exactly (
you didn't say)? If the problems started after an update of the video drivers, have you tried rolling back to the previous version? Have you tried to simply press the "Q" button to see if the absence of sounds at engines running stopped the problem? And for last, have you tried to borrow another similar video card to see if it's an HW problem?
Try one or more of the above suggestions and see if things go better. It may be a whole range of things... :-/
PS
For last try and strip from the livery of the plane(s) that gave you this problem the MipMaps with DXTbmp. Sometime it's all the MipMaps' fault that inexplicable problems with textures happen.

PPS
Two recommendations. First one: never, and I say NEVER update perfectly working drivers only because you're bored. It's the main source of all kind of problems. Update
only if strictly needed (
example: if the drivers you are using aren't able to work with a new software/game you want to use). Second: those with an older and less powerful CPU may profit installing a good add-on sound card and disabling the on-board audio system. On-board audio uses the CPU to work, while good quality add-on sound cards ([i]those above 20
There is no such a thing as overkill. Only unworthy targets.