Network problems in a Novell/NT environm

We seem to be experiencing problems on our network where we run IPX and IP. For example, I’ve noticed that NT login scripts run very slow on Win98 machines but fly through on Win95 machines. We are running Netware 4.11 and NT. I’ve noticed that NT login scripts fly on Win98 until I load the Novell client. Unfortunately, we cannot get away from IPX just yet. Any thoughts on why this is occuring? Thanks!