Intel chips seem to produce more heat and require more care in cooling design -- a trend they claim will be reversed.
But regardless of Intel's design efforts, the trend is to hotter and faster chips. Assembly will have to be improved.
The P4 series does.(pentium 4s are based on netburst)
I'm not so sure about those which belong to the centrino line. Those intel chips made it into laptops, PPC 970's didn't. AFAIK the current P6 architecture based chips are quite cooler than their PPC bretheren.
But even then, there are P4 laptops. No 970 laptops.(that I've seen)