TFS Performance issue after deploying server plugins

See more:

C#

TFS

Hi I am using TFS 2010 SP1 and I have created TFS Plugins using C# code.

That plugin will get the changes of the work item and update another database.

Everything is working fine but all the TFS User faces problem with low performance. I have increased the RAM of the server upto 8 GB but still no luck.

I have checked on tfs server performance and saw that suddenly w3wp.exe process uses all the memory and cpu usage is 100%.
While Remote Debugging I found that workItemStore.GetWorkItem(workitemId) uses more cpu.

When i Remove the plugin then TFS behaves normally with good performance.

I am not able to identify the issue.

So can any one help me to identify the issue ?