Hi Trevor
I don't know the mega pixels of that camera, or the file size, but I have some sample images here at just under 20 megs filesize, and as long as Qimage ultimate has created its cache copy, you should get a hi resolution image on screen (hover the mouse over the thumb and press spacebar) in about 3 seconds. I just timed a half dozen of them.

So we have two things to look at in Qimage Ultimate.
First I would make sure I have the proper settings in RAW OPTIONS with LIGHTNING RAW ticked and the rest of the goodies. See snap
When Qimage Ultimate sees images for the first time, it will now take a few extra moments to build the raw cache copies. After that, lightning fast.

The other thing that might slow you down is when you have turned on a few slow type filters in the editor.
These might include, Blemish removal, Noise filters, or Sel Clr filters.

That's what I can think of initially!!

Do you have any further information, file size, or exact key or mouse strokes?

Fred