Please do try these troubleshooting steps that may help in solving the issue.
- Start by removing the RAM's you added in your laptop and observe if the laptop will also overheat or not.
- If it does still overheat then proceed with opening your laptop and cleaning the dust off the fans and apply new thermal paste on both the GPU and CPU.
- But if the laptop will not overheat without the added RAM's you may need to verify if the RAM upgrades are compatible.
- Here's the compatible RAM upgrades for your laptop.
- http://www.crucial.com/usa/en/compatible-upgrade-for/Lenovo/lenovo-g50-45