[winewood]

1) Bill just said that the IHS does NOT behave just like a second TIM joint. As he is under NDA, one would conclude it must work better than predicted from such.

Ok.. it doesn't. Then is it for the worse or better? Didn't say.. can't derive from no data. Bill wouldn't accept no data understanding from others. You can't even determine to what degree or extent the difference. So, what is that telling us? nothing. I could say, the the cascase and lrww don't behave the same.. does that tell you anything?

Lets argue this point slightly. I have a pin size block and a lrww. Both will not behave the same on a simulator of a core vs. one with an IHS. The pin style block may not look good at all compared to a lrww on the core sim. Now on the IHS it may be very close. Why??? the lrww was made to a narrowly defined core hotspot. The pin would work much better with a spreader than would the lrww as it can work better with larger area heat sources like.. a TEC. However, we are not talking TEC cooling now, but IHS cooling. Are we cooling die's anymore?? In a way... no. We are cooling IHS's. Why are people afraid to change to the market?

Now you have testers with the core modeled heat die's, and everyone now is using the IHS. Can you really tell them how their block works with an IHS? Or are the testers just using a core because you like the pretty numbers? Take a die sim using a core heater, then place a IHS on it. Isn't that much closer to real world testing now than pretending the IHS doesn't exist?

I would assume that a smaller die in general will produce higher temperatures than do the chips with IHS

If you know there is a difference.. or assume it... then you must account for the changes in your sims. You know they aren't the same. You said it yourself. We wouldnt use a core to test a TEC cofiguration, because the core can't replicate the TEC surface or heating element. Why do it in this case...?