HDMI to Sims 3

I recently purchased a Blue Rigger mini display to HDMI for my 15" late 2011 MacBook Pro in order to play the Sims 3 through my Samsung TV.

Whenever I open Sims with the mini-->HDMI, the screen somewhat freezes on a magnified version of my desktop. However, without the HDMI converter in, Sims plays as usual on my computer. Before opening the game with the HDMI plugged in, the screen displays clearly and accurately onto my TV, it's only when I open the game that the desktop magnifies and does not load the game on the screen, although sound is playing through.

I know it is not the mini-->HDMI as I've tested it on a 2009 MacBook with the Sims 3 and all of the expansions installed. It shows up fine on the TV through that.

Any suggestions?? Thanks!