FTP Directory subfolders efficiency

Question

I have about 7000 folders on a FTP server. 300 of these will contain a subfolder named "ToSpecialFolder". I'm using the code below to return the wanted subfolders.

The call takes some time to complete, is there a more efficient way?

string[] ftpDirs = Directory.GetDirectories(ftpRootFolder, folderEndsWith, SearchOption.AllDirectories);