Just as a first measure, restart all the QlikView services and try again. Kind of like rebooting your PC
qvb is the reload engine on publisher. I am assuming you know what document is reloading during that time? If this is a report that did not peg the server previously, you will want to look at a few things. First, was the qvw modified? If the script gets almost all the way through (check the log), then it is possible that a cross join or multiple fields being joined was accidently created, resulting in an overload on the CPU while it tries to resolve. Another possibility is that the underlying database changed. Maybe a table that previously was not populated, is now and has caused a huge influx of data that the qvw might not be equipped to handle. Are multiple docs reloading at the same time? This could also cause a problem as well.
I have many times come across this issue.It might be any one of the following scenarios.
1. No optimisation is done to the report: Resolution: QVD's can be used.
2. If some reports are reloading and parallely while opening a report which has a table that has huga data it get the CPU Usage to 100. Resolution: End the process from the Task manager
3. If multiple Reloads are occuring: Resolution: Try to schedule it such that it doesnt affect the performance of the system
4. If the performance is always slow and the CPU usage is at a consistent 100% Restart the servers.
5. fIf its fluctuating kindly increase the RAM capacity.
Hope this helps you.