@Linux_in_a_Bit yeah i don't use the fiio much. and i couldn't really tell the difference between the laptop out and the ap80 either.

i conclude i don't have expensive enough headphones.

it wasn't until the hd599s that i started to hear a difference. at that level they did sound just the tiniest bit less muddy coming out of the dedicated units. (i guess the hd599 is just almost fancy enough; its in a twilight zone where some computers aren't powerful enough and it gets muddier sounding for people)