Well inregards to loss of sound quality, thats a well known fact with increasing cpu cycles. Theres no real way around it at present.

The "problem" is that your cpu supports hyperthreading. That means that 1 CPU actually acts (or the operating system sees it) as 2 seperate processors. This means that one signle-threaded application can never use more than 50% (as seen by cpu monitoring programs). Even in real SMP setups it would be hard for 1 single program to use more than 1 cpu 100%, since parts of the program always depend on each other. I'd say this is even more true on a hyperthreading CPU, as you have to remember hyperthreading != dual core (there is only 1 CPU core in your system). So, the usual tips apply here as well: try dynamic core, change output mode, etc...read some other topics about optimizing dosbox speed - and that will be the most you will get out of your system.

ah okay..
well, i've tried most outputs and i think overlay was the best alternative. as for the core, it didnt seem like it made any difference other than that some games started and some dident hehe..