What's the ideal healthy tempeature range?

it ranges depending on the video card meaning if its less efficient aka older graphics they tend to run hotter and now we're moving into making everything smaller to make it more efficient
as for laptop graphics they usually run hotter since there is less airflow than a regular case and some by design will have two heat pipes (one from the cpu and one from the graphics chip) going into a single heatsink out the back making the heat exchange less efficient

your 660m should not idle no higher than 60c and not go over 90 or 100 on load as 100c is boiling point for water lol

allright thanks

and yeah it's in a laptop. At the current time my nividia is 39 c
while the intel graphics card is like 40-45c

I have a y580 so I have one large side vent.
  and I should probably invest in one of those compressed air blasters or whatever they're called? to remove dust?
The thing with those is do I have to remove the bottom casing of my laptop to do so?