Peter,
Please tell us the best Preference settings for opening contact sheets containing large TIFFs or RAW files.
TIFFs are always going to initially be slow because their file size tends to be large (low compression ratio).
RAWs will load fastest if RAW rendering is turned off.
Contact Sheet sort method will have a direct impact on speed of loading a contact sheet. Filename and Modification Time sorting are fast, all other choices are very slow.
-Kirk
