Would the fact that my GPU temperature reaches like 109C while I box with my fan speed at like 90+% cause my computer to shutdown in an instant?

My comp never seems to shutdown like this for any other reason and only happens while I am boxing and not all the time. My GPU temp is always high 100c+ all the time, but I don't know what I should do to correct this problem as I didn't have it before?

Any thoughts to if that is the reason my comp crashes and if so, how do I solve the high temp of my video card? BTW its an ATI Radeon 4850