For some reason, if you buy your unit from a reseller that's had stock on shelves for a month or two, you might have to give the Shin-Etsu TIM about 24-48 hours of use to cure. I have noticed on systems in the lab that we install with fresh H50s from a couple boxes that have been under my desk for a couple of months, we see higher temps for the first 2-3 days than we do afterwards. I saw a 7C drop in temp, actually, without changing anything, just waiting 2-3 days. And you're right, the stock TIM is actually pretty good stuff once it's cured like this. It shouldn't need much time to cure if it's relatively new. No easy way to tell except for the Lot Code on the box, it should start with an 09XX or a 10XX, which translates into 2009 and the work week or 2010 and the work week. (Example: 0953 is the last week of 2009, 1005 would be the 5th week of 2010). This is manufacturing date.