Macbook Pro 2012 md101 gpu throttling When playing games on Macbook Pro 13 inch 2012 md101 under Windows 8.1 the temperature rises to 100 degrees pretty fast and gpu starts throttling giving a huge slowdown in games. Is this a normal behaviour of this Macbook? If not what should I do to fix this? 

This notebook has Core i5-3210M and Intel HD Graphics 4000

I was thinking about changing termal paste.
Yes this is perfectly normal behaviour. You can change the thermal paste if you want but you won't see any great difference in thermal levels. The Intel HD4000 GPU is integrated in the i5 die and CPU/GPU throttling is the main protection mechanism for thermal limiting .