So I replaced my thermal paste today after experiencing lag about 10-20 minutes of playing Dead or Alive 5. The lag is now gone. after 1 hour of playing, the max temp of the GPU is around 75-84 degrees while gaming and for the CPU it's about 70-84 degrees. These are the idle temps exactly 3 minutes after closing the game: http/puu.sh/iAQQ2/2608430850.png
The best you can do is install an app like speed fan. "During this test, the CPU of the IdeaPad Z580 reached a temperature of 98 degrees Celsius (208 degrees Fahrenheit) which did not cause a thermal shutdown but the CPU’s clock speed settled at 2.4 GHz during dual-core operation. During subsequent execution of Cinebench R11.5 and 3DMark06, Turbo Boost responded normally. In terms of gaming, we were able to reproduce this slowdown which limited the CPU to 2.4 GHz and 2.5 GHz operation while playing Battlefield 3."