It's not overclocked most of the times. I got the fan curves set like this (see attached).
On office work load, it never goes higher than 35C. On Cinebench r23 it goes up to 75C max (actually, it immediately goes that high and stays there, no matter how long the test is gonna take). On prime95 unrealistic scenarios, it went to 79C max.
I tried overclocking with the CPU boost motherboard option and intel's extreme utility... didn't have the time to go into OC more, but will do the following weeks. However, i've seen a minor temp increase, like 5C max on idle, and 2-3C max on heavy load.
I don't use the "dot/rice" method to apply thermal paste. I spread it on the IHS evenly... i have no idea if that makes any difference, but thought of mentioning it.
I think the washer mod will help people that have a pure flat cold plate, which is not the case in most cases... But as i said, i never really pushed it to the limit to see any difference. When i dive into oveclocking, it might make a difference... can't really tell.
On the other hand, if it is a wide spread issue, how come motherboard manufacturers don't correct this on production level?