LG usually is better than Samsung. It seems like you have Samsung.
I have 3 experiences w/ M1730 screens.
1 LG was great, 1 Samsung was horrible, and 1 Samsung was great, but not as good as the LG in colors (other than black though). The great Samsung did have better black looks than the LG though. The bad Samsung had horrible leakage.
What's the idle temp on it?
My cpu's idle @ high 50's (C) in hot summer apartment.
Haven't gaming lately, so I'm not sure how high it will go during games though.
If it keeps up, I would just call Dell, and ask for repairs.