What I'm interested to find out is if you have an ingame fps of say 37+ for gp4 and the TV is limited to 25 would it be fair to say it will run pretty smoothly on the TV, Fraps is giving me a return of only 20 fps with my GP4 so it's lower but still looks good.Mortal I was misleading, now I understand. Those are two different phenomena. 25/50 interlaced is how many times per second the electronic beam can travel across the screen to refresh the image. It's just the same that happens for a monitor. The higher the count the more stable is image and less tiring to watch.
FPS of a game is different matter: if you run GP4 at 37 FPS it is just like you were watching a burst of slides. Each second 37 different ones are displayed. Of course, since reality comes in a continuos stream instead, the more the FPS the closer is you illusion of reality, but this is another matter.
So if you are watching GP4 running at 37 FPS on a PAL TV you are just watching 37 still pictures each second, while the image on your TV screen is completely refreshed 25 times in a second (25 each half of the screen hence 50 interlaced) regardless of what appears on the screen.
More FPS = smoother sensation of motion, greater sensation of speed and more lifelike experience.
Higher the refresh rate of screens (monitors or TV it doesnt matter) = more stable image and less fatigue for your sight regarless of what's happening on the screen.