Dynamics AX 4.0 SQL Server 2005 Hanging Issue


We are used Dynamics AX 4.0 with SP1 and SQL server 2005 SP 2. Production server around 80 GB database. My issue is when we used some inventory transactions such as transfer oreders postings at that time SQL server performance goes up tp 99% and it wont release take long time. At that time other users also coundn’t retrive any information from the application it self. It becomes not responding screen with white blird.

So at that time AOS server with normal perormance. so due to that reason i have to restart the dynamics service to get the system normal. any body can help what shuold be the root cause for this? FYI this happend once a time in particular day.