You're using on-board sound? Ya, you'll have difficulties with that. I'm using the on-board sound on my ASUS A7V600-X and the drivers haven't been updated since 2003. I was doing better in terms of sound when I still had my old Creative Labs SB-Live! Value. As soon as I can warrant the expenditure, I'm gonna go out and grab an Audigy2 Value, 'cause on-board sound is CRAP! When ever things in FSO get dicey (Inferno mission "Nemesis" is a noteable example) suddenly all of my game sounds are replaced with loud buzzing noises. I then have to pause and turn down the volume, but then I can't hear the missile launch sound or know when a nearby beam cannon is powering up and about to vapourize me.
Your system power seems decent. In most respect it out-classes my system. In addition to the -pcx32 and -loadonlyused tags, there are a few more tags in your list, which are somewhat redundant or not as useful. -ship_choice_3D just replaces the ship selection ani in the preflight screen with a rotating image of the actual pof file, like in the techroom. Its realy only useful for anyone making a MOD that doesn't want to have to make a new ani for it. -alpha_env will work better than just standard -env, but not all canon ships have alpha-environment shinemaps yet, which causes any ship without these to look somewhat strange. I'd advise keeping to just -env until Lightspeed completes his work on these. -decals, while a cool effect, are still a bit buggy and may have some memory leaks. You may get a performance boost if you disable this feature.