Win 10 64 Home Pro, 24 G ddr3 RAM, gigabyte mobo 1156, i5 CPU, GeForce 710

There's a lot of snap crackle and pop in my audio feed when listening especially to music. It kinda sounds like clipping. I have a set of Logitech computer speakers with a subwoofer and I've made sure to not overload the volume on the various dials. I've got a Soundblaster G6 connected via USB. I've compared the sound of that connection vs the onboard sound card and the same stuff happens. It's NOT in my network wifi. It's in the machine. Somewhere. The mobo is at least ten years old. I'm considering upgrading but I hate to waste DDR3 RAM (24 g) when changing to newer mobos. Otherwise, I've got a reasonable setup. Are mobos still available w.DDR3? Anybody got a good used one?

I"m removing USB devices one by one to see if any of them are sucking signal away from the audio. There is something to be said for this procedure but it hasn't been a cure. My best sounding app is the win provided Groove. I'm at a loss on this one. Ideas?