FPS Question

I have strange problem with fs9 so here goes.My system is basicly this AMD 28001gb ram80 gb HDBFG Nvidia 5500 OC 256 mb cardNow with that in mind FS9 runs great most of my graphic sliders are almost all the way to the right with some AI traffic on and PMDG 737 running at KSEA I can fly around the area with framerates easily in the 30s and 40s :)Now for the kicker... As soon as ASV6 loads the clouds BAM!! my FPS drop to 10 to 14. I have tried everything to tweak it out but nothing helps even running the lowest res. clouds that ASV6 has and no change. So heres the question. Is my graphics card hitting its limit or what?. Would I be able to get back into the 30s with a new card or is it something else I havent thought of. Seems like the higher I turn up my graphics sliders the better FS9 runs and I get higher FPS but when the clouds hit look out. I have tried lower slider settings and it makes it worse.I was wondering if maybe my graphics card does great with scenery but poorly with clouds any ideas?