I haven't read maximumPC in a long time. Though the overheating issues with macs is the newer macintelosh line, not the "older" powermac line.
AFAIK.
But it does show a trend of sloppiness on their part.
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 thermal paste issue was with the Intel line and I've seen reproductions of the official Apple manuals that show how to apply thermal paste -- and wow were they screwed up. Nobody globs on thermal paste like those assembly instructions indicated. That much thermal paste will end up being an insulator.