I have a Dell XPS 15 which I use to play mainly sports games, FIFA 13, NBA 2K13 etc which all run perfectly fine on max settings with the laptop plugged into my monitor via vga cable (with a mini displayport converter). The monitor is full HD so I play both the games in full HD with no lag or any problems whatsoever.

As soon as I use an HDMI cable instead of VGA, the framerate drops occasionally whilst playing, does anyone know any reasons for this? I've tried 3 different HDMI cables on 2 different TV's (both full HD) and on my monitor. 

Everything else works fine when connected via HDMI, watching movies, browsing the internet etc so the problem is just when I'm playing games which I'm confused about as the games work fine when the laptop is connected to the monitor via VGA. None of the TV's I've tried can support VGA at 1920x1080 so that's no help.

The only thing that I can think of is that I'd need to buy a better quality HDMI cable but I've read a few different opinions about them, some people say that the quality does make a difference and others that say that it doesn't make a difference.

Any help would be much appreciated. Thanks