I think USB soundcard uses its own sound processor to process sound, so a PC game may run a few video frames faster on a cheaper laptop because the processor on the laptop does need to process sound data because the processor on the USB sound card help process the sound data.
I remember reading a sound card article online many years ago where installing a sound card on a desktop PC made the computer run games a few video frames per second faster.
Some sound cards also sound louder, and more realistic sound than the sound chip on cheaper laptops, so using a higher quality USB sound card can make games sound more realistic when hooked up to a pair of higher quality speakers.
I remember reading a sound card article online many years ago where installing a sound card on a desktop PC made the computer run games a few video frames per second faster.
Some sound cards also sound louder, and more realistic sound than the sound chip on cheaper laptops, so using a higher quality USB sound card can make games sound more realistic when hooked up to a pair of higher quality speakers.