Poor TIFF Performance (Regardless of Default App)

I at least believe this is a very different problem than what I've found
elsewhere in Newsgroups and through Googling about it...

I'm in IT and have about 80 users. Not all users are affected in this way
but there's little variation between each user's computer when it comes to
installed software and configurations since I lock things down fairly tight.

But we have a problem with TIFF files. Certain (seemingly random) users
have to wait about 2-3 seconds to open up ANY TIFF. Office Picture Manager
(2003), Windows Picture & Fax Viewer, Paint... it will not matter which
program I set as default.

I've tried the OIS catalog bit with Office Picture Manager - no difference
whatsoever.

These are very beefy dual-core computers and opening these TIFFs should be
instantaneous for everyone, not just 95% of my users.

Photoshop users are unaffected with the problem.

Any suggestions/help is appreciated.

Matt