So yesterday I bought a nice little compaq Armada E500. It worked nice and all, but it only had a celeron 550, so I swapped its mobo with one having a Pentium III 850MHz. It performs much better now, but there is an issue that wasn't there before : the speakers now output some hiss constantly (even if I turn the volume all the way down). Since this laptop has REALLY good sound normally, this is very annoying ...

What could be the cause of this ? When I first got this motherboard years ago, it didn't do that. Could that be a bad cap issue ?

I can take photos of the celeron 550MHz mobo if you want to know what components are on there.