Hint: sometimes the soundcard makes all the difference. I’ve plugged the same mic into an onboard card and later into a Soundblaster live 5.1, the difference was night and day. The onboard Realteks and the like add disgusting amounts of noise. Apparently because there is such a thing as being too close to the motherboard or the cpu.
Yeah, actually I used to have a laptop where you could hear when somebody was scrolling text, because the sound card picked up EM interference from the video card. Crazy, but I think discrete is generally best if you can swing it. For laptops, USB audio may work for better EM isolation.