Of course most of todays video cards will run Shaiya, some better than others.
Quite right - turning down some of the effects, even going to 16 bit colour can help speed things up.
It's also worth checking to see you have the current release of driver for your GPU.
Set a system restore point before updating any new drivers; as with so many games out there
they (ATI/NVIDIA/etc..) don't always get it right with the new driver version.
Providing your rig has adequate memory and meets the spec given by AGE the most likely source of lag will be the network.
(as we've all been finding out this week of hell)