Win2000 and Wireless

Recently I have converted a Lab of 20 PCs to Win2000 from Win98. This Lab is a wireless lab with 2 wireless hubs. Under Win98 the speed was as fast as a hard wired lab. The only change is to update to Win2000. Now the performance of the PCs is terrible to the point of being unusable. I am considering hard wiring the lab to retrieve performance.I have a valid reason for wanting to retain the wireless infrastructure.

Can anyone suggest any config changes to Win2000 that will give it the performance of Win98?