Slow saves on Win XP /4.83 to Novel 5.1

We have recently begun implementing Win XP Pro machines into a former Win 98 enviroment and have noticed that when saving a file from a WinXP Pro machine to the network drive, it takes up to 500% longer than it use to on a Win 98 machine. (Sometimessaving W97 Excel file fails all together) We are running Novell client 4.83 on the XP machines using IPX conneting to a server running Novell 5.1 sp5. Any one have any idea what could cause the slowdown? Is there some known issues with XP and Novell?
Thanks