I know I said I wouldn’t respond… so sorry.
You’d be amazed…l I’ve seen little 8bit 2MHz micros hummmm… 30dBs over… and my customers were likewise surprised… It’s all about the layout, but 72MHz is fast in EMC terms and quite capable of causing severe problems unless every precaution is taken. Limits are actually set stupidly low, I think mostly to create non tarrif trade barriers.
As I said the multilayer board gives confidence… but not too much. Must confess I had a bit of a ‘cold sweat moment’ when somebody reported an EMC issue. I really don’t want to have to get my spectrum analyser working again!!!
BTW could you sort my post counter it seems to have been inadvertantly reset.