gpu core temperature for inspiron 15r with ati 5470 (512mb)

well last night while playing modern warfare 2 i heard loud sound coming from the fan testing from GPUZ  I found that gpu temperature ran as high as 77C i m really worried will it fry my gpu?http://en.community.dell.com/cfs-file.ashx/__key/CommunityServer.Discussions.Components.Files/3518/7382.GPU_2D00_Z-Sensor-Log.txt please some one help is it normal and btw idle temperature is around 50C even though it is winters right now