Avatar moving lag

I just upgraded my dual 1.8 G5 PPC (I know) from 10.4 to 10.5. Once in a while I get acceptable SL performance but I've noticed since the 10.5 upgrade that there is an annoying delay in forward movement commands. Turning left and right is instantaneous but there is a bad lag when moving forwards or backwards. And sometimes it is with only one of my Av's. I have had an alt online at the same location with NO lag while the other Av lags.

Or did SL upgrade something at the same time - does everybody experience this?

That sounds like plain old server- or network-side lag, it could be coincidence that you upgraded OS X around the same time you started seeing it.

The viewer will display swiveling in place (left and right arrows without shift) right away, even if you're disconnected from the sim. Actual movement (forward/back, or left/right with shift held down) won't begin until the keypress is transmitted to the sim and the sim acknowledges it.

Many networking tweaks can *add* latency in an attempt to increase throughput, so if you've added anything like that you might want to remove it. But more likely it is SL or an outside network slowing things down a little.