I have installed OpenWRT on an old WRT54g router I had in a drawer. Installed QoS and then configured it to give maximum priority for VoIP. After doing numerous tests on this, I have noticed that my XNet speedtest consistently drops when I have QoS turned on, even though I have nothing else running on the network. (Ie, no VoIP calls or anything that is configured as higher priority.)
So, my question is would you expect this? I don't know alot about QoS, but I thought it would only have an affect when you had multiple things happening at once (other than perhaps a slight drop due to the overhead). But I am seeing my downstream speed go from 3Mbps to ~2.4Mbps, and upstream going from 700kbps down to about 520kbps.
Any advice on why this is? If you don't get this, perhaps I should try a different implementation of QoS.