Download Everest home edition (search from google)
And then in the program go to
Computer>Sensors
THere u will see ur GPU (videocard) Temperature
Close all games ur running and then tell what temperature GPU u have
Its normal between 40-50 CELCIUS on IDLE
If its overheating u might try putting a fan blowing towards ur Videocard
Like i did It went from 60 celcius idle to 45 celcius Im waiting for my big fan to
be repaired.