I have an iMac 27" coming to 3 mths. I'm facing this problem since day one. It didn't really bother me initially but felt quite strange as it should not happen this way. Whenever I send out an email, it will take between 30 to 45 sec before it send off even if the mail merely contains a few words. I checked my server speed and everything is fine as I'm able to download images pretty fast. It never happen before to my previous old MBP. My iMac is EC.