70C on the GPU when it isn't being taxed is high.
SpeedFan is detecting the GPU twice for some reason. It is seeing it as a nVidia GPU and as a LM75 sensor chip. The LM75 is unlikely to actually exist since the rest of your system is using a Winbond sensor chip and the values for the GPU and LM75 are the same.
That 70 degree figure is suspect. The attached screenshot was taken less than three minutes after the computer was started up after being turned off for 15 hours. Would that GPU really heat up that fast?
tanstaafl.