I load 800 plus images into i-photo at a time. In order to view them all the right way up I have to rotate them. If I rotate 5 or more at a time the software doesn't like it and seizes for 20 seconds.

I have 90% of my memory allocated to Photoshop (500m ram).

Any ideas anyone?

Welcome to The Mac Forum.
In your post, you mention Photoshop & iPhoto. We need to know what program you are using in order to assist you.
Thanks,
Sysops