Can anyone help with an LCD HDTV issue?

A while back I got a new LCD TV. It’s really great and everything, like having God in your living room. But when I’m playing Playstation 3 games, whenever there’s movement in many games everything seems a little blurry. Why does that happen? And is there some way to rectify this? Here are the specs for my TV if this helps in finding a solution; 1080p, 120hz and I’m using an HDMI cable I bought for 16 dollars. The TV is from LG.

This doesn’t ruin my gaming experience, I’ve had the TV for a bit and I’m fine with this, but if there IS a way to stop the motion blurriness that would be pretty cool. Is there anything in settings I should do? I looked through them in detail, nothing really does anything. They’re mostly for how the picture comes in rather than what I’m looking to fix. Should I get a better HDMI cable? I heard some are much better than others. How true is this? There has to be a reason why some are ten bucks while others are a whopping eighty dollars.
Or maybe there’s some settings in my PS3 I should look at? I’m pretty sure on that end, I’ve got everything down though.
Any ideas? Thanks.