Unfortunately, this is not at all uncommon with LCD.
You need to upgrade to a better quality rig that can handle the fast motion.
I have recently bought a Samsung UE40f8000 and have hooked my pc up to it, but am having some issues with the picture when in motion. Whilst the picture looks amazing most of the time, in pretty much all games to some extent, I get this dark flicker or smearing when I move the game camera
Its quite bad in DA2, as hopefully shown in the link above if you look at the trees when I flick the controller.
This doesn't happen on my pc monitor, and I have tried turning off every option on the hdtv, one by one, but it doesn't seem defeatable (including eco settings, game mode, renaming input to pc etc).I do have some luck when I increase the brightness of the tv (or lower the darkness), and it seems to only affect dark objects. It also happens on my ps4 too. I'm thinking this is either a fault with my particular tv, or a by-product of a feature that I am not able to switch off.
I'm just wondering if anyone else experiences this, whether this is a common effect when gaming on a hdtv, or if you think its a fault and worth pursuing with samsung? I did drop Samsung support an email (more or less saying what i've said here), but they weren't very helpful and suggested enabling/disabling certain picture options, all of which I had tried.