Improving ArcGIS Engine performance with file geodatabase

We have an ArcGIS Engine-based production system. It is a legacy system handling data in shapefile format.
We migrated it to a file geodatabase and got a better performance. However, we are noticing varying performance (12 hours range) for the same volume of data. We noticed the same when we ran the tool on a different system with the same configuration.

Any suggestions to address the issue?

Sharing samples:

CopyTemplate() took 2400 ms,2900 ms ,4800 ms at different times.
ImportGCS2UTM() took 2800 ms,2900 ms,3761 ms for different runs

There 40 feature classes(overall 1000 records) and 1000 Lakes.

A similar trend observed for all FGDB transactions.

  //Copy a template GDB to destination 
   //Rename it to <LAKE>.gdb
   public string CopyTemplate(object passedTuple)
        {
            var stopwatch = new Stopwatch();
            stopwatch.Start();
            try
            {
                var myParamObj = passedTuple as Tuple<string, string, string>;
                string strUTMGDBemplatePath = myParamObj.Item1; // For a given LAKE, get the UTM zone in which it falls .
                string strLAKEPath = myParamObj.Item2;
                string strLAKE = myParamObj.Item3;

                Type factoryType = Type.GetTypeFromProgID("esriDataSourcesGDB.FileGDBWorkspaceFactory");
                IWorkspaceFactory pworkspaceFactory = (IWorkspaceFactory)Activator.CreateInstance(factoryType);
                string temp = strLAKEPath + "" + strLAKE + ".gdb";
                // Delete <LAKE>.GDB if already exists
                if (pworkspaceFactory.IsWorkspace(temp))
                {
                    IWorkspace pWorkspace_GDB = pworkspaceFactory.OpenFromFile(temp, 0);
                    IDataset pDataset = (IDataset)pWorkspace_GDB;
                    if (pDataset.CanDelete())
                    {
                        pDataset.Delete();
                    }
                    if (pWorkspace_GDB != null)
                        Marshal.ReleaseComObject(pWorkspace_GDB);
                }
                // Create new workspace name objects.
                IWorkspaceName sourceWorkspaceName = new WorkspaceNameClass();
                IWorkspaceName targetWorkspaceName = new WorkspaceNameClass();
                // Set the workspace name properties.
                sourceWorkspaceName.PathName = strUTMGDBemplatePath;
                sourceWorkspaceName.WorkspaceFactoryProgID = "esriDataSourcesGDB.FileGDBWorkspaceFactory";
                Type factoryType2 = Type.GetTypeFromProgID("esriDataSourcesGDB.FileGDBWorkspaceFactory");
                IWorkspaceFactory workspaceFactory = (IWorkspaceFactory)Activator.CreateInstance(factoryType);
                // Copy this UTM template GDB to the LAKE folder
                workspaceFactory.Copy(sourceWorkspaceName, strLAKEPath, out targetWorkspaceName);
                // Rename the GDB as <LAKE>.GDB
                // pworkspaceFactory = new FileGDBWorkspaceFactory();
                IWorkspace pWorkspace_GDB = pworkspaceFactory.OpenFromFile(targetWorkspaceName.PathName, 0);
                IDataset pDataset = (IDataset)pWorkspace_GDB;
                if (pDataset.CanRename())
                {
                    pDataset.Rename(strLAKE);
                }
                Marshal.ReleaseComObject(workspaceFactory);
                Marshal.ReleaseComObject(targetWorkspaceName);
                Marshal.ReleaseComObject(pWorkspace_GDB);
                Marshal.ReleaseComObject(pworkspaceFactory);
                workspaceFactory = null;
                targetWorkspaceName = null;
                pWorkspace_GDB = null;
                pworkspaceFactory = null;
                stopwatch.Stop();
                long elapsed_time = stopwatch.ElapsedMilliseconds;

                return strLAKE;
            }
            catch (Exception ex)
            {
                return string.Empty;
            }
        }


 public void ImportFileFeatureClass_GDB(IFeatureClass srcFeatureClass, IFeatureClass tgtFeatureClass, string strLake)
    {
        try
        {

            IFeatureBuffer ddFBuffer = tgtFeatureClass.CreateFeatureBuffer();
            IFeatureCursor dbbFCursor = tgtFeatureClass.Insert(true);
            IFeatureCursor srcFCursor = srcFeatureClass.Search(null, true);
            IFeature objFeature = srcFCursor.NextFeature();
            while (objFeature != null)
            {
                try
                {
                    for (var i = 1; i < objFeature.Fields.FieldCount; i++)
                    {
                        string fldName = objFeature.Fields.get_Field(i).Name;
                        if (tgtFeatureClass.FindField(objFeature.Fields.get_Field(i).Name) >= 0 && !objFeature.Fields.get_Field(i).Name.Equals("Shape"))
                        {
                            int indx = tgtFeatureClass.FindField(objFeature.Fields.get_Field(i).Name);
                            if (tgtFeatureClass.Fields.Field[indx].Editable)
                                ddFBuffer.set_Value(tgtFeatureClass.FindField(objFeature.Fields.get_Field(i).Name), objFeature.get_Value(i));
                        }
                    }
                    ddFBuffer.Shape = objFeature.Shape;
                    dbbFCursor.InsertFeature(ddFBuffer);
                    objFeature = srcFCursor.NextFeature();
                }
                catch (Exception ex)
                {
                    
                }
            }
            dbbFCursor.Flush();
            Marshal.ReleaseComObject(dbbFCursor);
            Marshal.ReleaseComObject(srcFCursor);
            GC.Collect();
        }
        catch (Exception ex)
        {
            
        }
    }      

  private void ImportGCS2UTM(IWorkspace pGDBwrkSpace, string strGCSdatasetName, string strLake)
    {
        IFeatureWorkspace pFtrWorkSpace = pGDBwrkSpace as IFeatureWorkspace;
        try
        {
            IFeatureDataset pGCSDtSet = pFtrWorkSpace.OpenFeatureDataset(strGCSdatasetName);
            IEnumDataset pEnumDtSet = pGCSDtSet.Subsets;
            pEnumDtSet.Reset();
            IDataset pSrcDtset = pEnumDtSet.Next();
            while (pSrcDtset != null)
            {
                IFeatureClass pSourceFC_GCS = pSrcDtset as IFeatureClass;                    
                IFeatureClass pTragetFC_UTM = pFtrWorkSpace.OpenFeatureClass(pSourceFC_GCS.AliasName + "_UTM");
                if (pTragetFC_UTM != null)
                {                       
                    ImportFileFeatureClass_GDB(pSourceFC_GCS, pTragetFC_UTM, strLake);
                }                    
                pSrcDtset = pEnumDtSet.Next();
            }
            if (pFtrWorkSpace != null)
                Marshal.ReleaseComObject(pFtrWorkSpace);
        }
        catch (Exception ex)
        {
            if (pFtrWorkSpace != null)
                Marshal.ReleaseComObject(pFtrWorkSpace);
            
        }
    }