Cursor Movement Delay

We have a new Dell Precision workstation with Windows NT 4.0 that just came in-house. After the initial login, the cursor movement on the screen is extremely sluggish. In other words when the mouse is moved, the screen cursor takes a few seconds to figure out where its new position is. This behaviour lasts about twenty minutes and then (for some unknown reason)the cursor tracks properly. If anyone has experienced this behaviour and knows how to fix it, I would appreciate your input. Thanks.