Better check your math... 60C * 150% = 90C not 120C
Also your reasoning is flawed... I don't know if the 50% figure is correct, however producing 50% more heat does not mean that a chip will run 50% hotter. You are not taking several things into account including the ambient air temperature and the heat dissipation properties of the heatsink.
I got a load temp of around 50C with my old E6700 now I get 79C with my quad core
and oh yer in core temp it says the thermal barrier for quad is 100C and the 6700 was 70 (I think)