In regards to installing the heatsink, I just followed the instructions it came with, but I must tell, I can easily move it to the left or right.
Why do Thermalright make the same mistakes over and over again? Do they never learn from them?
There was the same problem with the LGA775 mounting kits, they just don't apply enough pressure to the CPU's IHS and can be moved around slightly. First make sure you have the screws screwed in as far as the springs will allow. If you already have, take the HS off, and put a thin washer in between the mounting X and the heatsink base, this will make it much more secure once you remount it. Just remember to clean away all the TIM with rubbing alcohol and apply it again.
Like this except it doesn't have to be rubber:
Also, you did lap your TRUE, right? 90% of them have VERY convex bases and need to be lapped.
And BTW, you really need to show load temps, idle temps mean virtually nothing.