Photoshop :: Hardware - Rotating Large Number

We get about 50000 photos in a short period of time, about a month, that we need to correct, label, convert to CMYK and rename very quickly. We've gotten good and fast at all of these, but rotation still gives us a lot of trouble.

We have to use Explorer to do a manual sort on the photos before we do anything else (using the expedient of an LCD monitor rotated through 90 degrees). We seem to run into trouble later, when using Bridge to manage the rest of the work, because the thumbnails in Bridge don't always update to reflect the file's actual state (rotated or not); the old File Browser did have the 'rotation pending' flag, and supposedly did understand the orientation setting saved by the camera, but not always. One way to deal with this is to rotate the files before Bridge encounters them, but this has involved a huge time hit.
So this part of the potential solution involves asking you all for advice regarding dedicating a machine to doing this and nothing else - I need for it to be lightning fast, like 2-3 sec. max per rotation,