1 minute ago, JakxterX said:
I didn't add any thermal paste because I thought there is some pre applied on the stock cooler .
There may actually be paste pre-applied. I didn't use the stock cooler. I upgraded to a different one, which also came with thermal paste. However, the thermal paste that comes with the cooler usually isn't as high quality as something you could buy yourself, and it's always good to have some laying around in case you need to replace the paste or apply some to something else. In the end, it's up to you. If the stock cooler comes with paste, and you trust it, then you can just use it if you want.