Cambridge Azur 851 D- Dac Question

Please don't flame me....I apologize in advance for my lack of knowledge regarding digital audio. With that said, I recently purchased the 851 D. Out of the box the default for the USB connection was a USB 1.0 software. When I used this the unit displayed 96 khz. The sound by the way was very good. However the manual instructed you could also download a USB 2.0 driver. When I did the unit displayed 44.1 khz. BTW- The sound in this mode was also outstanding. My questions are: the unit advertises the it will upsample to 192 do I achieve this? Do I actually want it to upsample to 192khz? All of my files on my computer are 320kps.... I'm just wondering if I have a setting not set correctly or is this typical of a DAC while playing audio files off a computer via a USB A TO B cable.

Any and all help would be appreciated. Thanks in advance.