Performance Problems

[Urkle]

Well I see two performance hindering issues with your system..

One the Duron.

Durons are the Celerons of AMD. Very little to No CPU cache which makes them horrible for Gaming. What you are probably encountering is when there are enemies going on you are dealing with the AI, physics, graphics, and sound systems all at once and the CPU cache (or lack of) can't handle pumping the instructions fast enough. Switching to a different CPU (a non duron AMD for example) would improve things considerably. My "development" linux machine is very comparable to your system, (geforce 6600 w/ 256MB, and 1.5GB of ram), but I have a full AMD Athlon 2100+ (which is a 1.7GHz CPU). I also run things at either 640x480 or 800x600.

The other USB sound.

This just adds extra load on your CPU. USB is "host driven" so the CPU is doing all of the work, where as *most* on-board cards, yes are slightly host driven, at least they benefit from DMA transfers so there is less work to be done.. A real card would offer even more sound offloading.

Basically.. You need something faster and with more Cache in the CPU.