Thanks guys,

The files are very big.
The jpg of this building is 19.05 mb and there was quite a bit of waste on the image to be cropped. The tiff I made it from is 1.07 gb.
I am using Bridge and on all my Mac's, maybe other viewers would work better. I had this problem with the Dell at work and it is a workhorse.
In Bridge if you zoom in it clears up. It is the opposite usually, when you zoom is when it lags and sometimes freezes if you have to many files open.