You certainly were in situation to read somewhere or to see for yourselves that with same settings and hardware, someone has lower temperatures then you, and better overclock respectively. Reasons should be looked for in bad connection between PTD and cooler. Bad connection is the consequence of using bad paste or its irregular depositing. However, sometimes happens that processor or cooler are „guilty“.
Modding 
You certainly were in situation to read somewhere or to see for yourselves that with same settings and hardware, someone has lower temperatures then you, and better overclock respectively. Reasons should be looked for in bad connection between PTD and cooler. Bad connection is the consequence of using bad paste or its irregular depositing. However, sometimes happens that processor or cooler are „guilty“.