Database realy slow after restore

Hi,
I have a C# application running of an embedded Firebird database.
The program becomes very slow if the database is restored, here are that bits of code that do the backup and restore. Do I have to set a flag or something to tell it that it is a full backup?

//code that dose baackup
FbBackupFile dbFile = new FbBackupFile(backupfile.FullName,(int)database.Length);
FbBackup fbBackup = new FbBackup();
fbBackup.ConnectionString = DbUtils.ActualConnectionString;
fbBackup.BackupFiles.Add(dbFile);
fbBackup.Options = FbBackupFlags.IgnoreLimbo | FbBackupFlags.NoGarbageCollect;
fbBackup.Execute();

//code that dose restore
FileInfo bakFile = new FileInfo(sfdBackup.FileName);
FbBackupFile dbFile = new FbBackupFile(bakFile.FullName,(int)bakFile.Length);
FbRestore fbRestore = new FbRestore();
fbRestore.ConnectionString = DbUtils.ActualConnectionString;
fbRestore.BackupFiles.Add(dbFile);
fbRestore.PageSize = 4096;
fbRestore.Options = FbRestoreFlags.Replace;
fbRestore.Execute();