Flickering horizontal line in FCP playback

I just upgraded my old 15" MacbookPro to a new 15" MacbookPro (Non-Retina Display). Just like my last one, It's primary use will be FCP editing. Like most editors I am still running FCP7 and have not upgraded to FCPX yet. When editing in FCP and viewing video played in the timeline and also in the viewer, I am noticing flickering scrolling horizontal lines occasionally when I play any footage. The lines are mostly apparent when there are quick cuts from one shot to another or if the footage contains quick camera movements. It appears that the next frame is being introduced before the previous frame.

The lines do not appear when using any other applications, and the video looks fine when I export the canvas and play it full screen using Quicktime. This only happens when I play video in FCP. I tried opening the same project on my old laptop and the lines do not appear.

I called AppleCare and they really didn't have any help for me. They said FCP 7 was never fully tested to run on Lion. Also, support for FCP 7 has expired and it is no longer offered. Does anyone know what these "lines" are called? And how to achieve smooth playback? I'm working with AppleProRes 422 HQ footage in a 1920x1080 HDTV 1080i , Square pixel, 23.98 FPS, with Apple ProRes 422 Hq Compressor sequence setting.

Stats:
OSX v 10.8.1

FCP v 7.0.3
Processor 2.7 GHz Intel Core i7
Memory 8 GB 1600 MHz DDR3
Graphics NVIDIA GeForce GT 650M 1024 MB

Attached are some screengrabs of the problem lines.

If it's not there in the final QT exports is it really a problem? Although i'd imagine it to be slightly irritating if previewing a sequence to a client via your monitor, in my experience this is a common playback issue on the Canvas only. Just in case i'd also double check your frame-rates/footage and sequence settings and ensure the correct match,

Bluey,