ALT+TAB and disappearing plane textures.

Hi all,Here's a problem that's been bugging me for quite sometime. Looks like I may have found a solution, but it's too early to say for sure.PC Specs:AMD64 3000+ on Asus K8N2x512megs DDR400, Hynix (2.5-3-3-6)Leadtek GeForce 6600GT, 128megsDefinition of problem:ALT+Tab)ing between FS in fullscreen and Acrobat reader/ Firefox /Explorer, continously for a large number (>30) of times causes - 1. Temporary slowdowns in FS, 2. Plane textures to disappear in external view, and 3. Total FS freeze/lock-up eventually or when switching to Window mode (ALT+Enter).100% CPU usage is observed w.r.t. FS9 in Task Manager and I have to kill FS9 to free up the system. The more complicated the addon, the quicker it happens (eg. in PMDG737, LD767). I need to alt+tab a lot as I read guides/tutorials in pdf format instead of printing them out - which imho is a waste of resources. I've tried shutting down all background apps too.I've tried various drivers, different driver optimizations, almost all driver/FS9 AA+AF combinations and display settings. This problem has persisted even after re-installing FS and running it without any FS9.cfg tweaks.I haven't observed this problem today after making a few changes - Installed modified OverDrive Apocalypse 77.76 drivers. <--- tried FS9 AA, Driver AADisabled AMD Cool 'n Quiet in the BIOS (while benchmarking). <-- most likey culpritLooks like I may have something here, but checking everytime I make a small change needs that I run FS for around 40 mins and ALT+TAB a lot. Has anyone here experienced any issues with AMD Cool 'n Quiet? Appreciate any help.Thanks in advance,Keith