I'm working in an SD project and recently, Video Preview on my 2nd DVI attached monitor has started acting strangely. In a sequence, it will not up-date in real time - just up-dates when I finish playing the seq. Same if I match-frame from the canvas - but if I load a clip into the viewer the reverse happens - video plays at 30 fps in the preview monitor, but doesn't up-date the viewer until I stop playing.
I can scrub thru footage and both screens seem pretty close.
UNLIMITED playback is not available on my timeline - I have lots of large stills and a mix of lo-res formats all up-rezzed to 720x480.
This also happens in other projects where I've never seen this.