Rob 1

20 degrees celsius is 68 degrees fahrenheit. That's slightly less than room temp in an average room. So you can't expect that.
But I would expect no worse than upper 30's celsius.

When you say you put the right amount on there, did you do the small dot of it in the center like they say?

I know it sounds wrong, but I've had best results using several small dots, and then spreading as thin as possible of a layer with a used razor blade from a box cutter.

If I mess it up, i'll do it again until I have nearly a perfect layer on there. VERY thin.

And my Zalman copper 7700 series cooler kept my E6600 mid and upper 20's celcius.

Also, keep in mind that Arctic silver temps do lower several degrees over time.

Just like the company says it will do.