I have a week 29 retail from buy.com I could only get 850mhz and no more. I was never over 45C. I took out the cpu. I erased and applied the pencil again. I also checked make sure the temp sensor was in the right place. I thought possibly it might not be touching the cpu. It was in the correct place. I rebooted and boom I have 900mhz. I have not tried to go higher yet. I would recommend that if you are not real hot but can not get a higher speed that you erase and apply the pencil marks again.