the vf 700 does not have heatpipes. heat pipes are used to collect vapor and condense it and return it to the base of the heat sink. consider boiling water, no matter how much energy you put into it, it always boils at 100*C, it just boils faster. it is the same thing here except the liquid boils around 45*C so your gpu never gets hotter than that.
thats all i know, no clue as to high high u can go.