Intel went from soldered lids to having thermal grease/paste between the IHS and the die. The attraction of de-lidding started when people figured out Intel was using crap thermal paste, either the paste was bad or there was too much of it. So they de-lid the thing, cleaned up the OEM paste and applied stuff like IC Diamond on it and placed the lid back on. I believe this started on the i7 2xxx series processors (where the thermal paste was REALLY bad), but I'm not sure if de-lidding the current stuff have the significant impact it once had (The guys doing it on the 2xxx series had temp drops of like 25+ degrees Celsius from CoreTemp).
That exactly is why I never understood why people want to de-lid their CPU's. Screw the thermal paste, just put on a better cooler/heatsink. Same difference! Why risk damaging your expensive processor?
Wasn't Sandy Bridge the last one to be soldered, which matched the 2xxx series? I believe Ivy introduced the TIM.
If your thermal limitation is between the CPU die and heatspreader, placing a larger cooler on top of the heatspreader isn't going to make a difference.
It believe that is correct, the 3xxx series was the introduction of that stuff. The rest of my post still stands though.
