I am always amazed by the fact that when ever i think that macs are getting competitive, these x86 guys are frankly quite out there ahead by 10 miles. I just read on anandtech that dual core Opterons (retail boxes!!) are 299$. AMD opteron 165 - Dual Core 1.8 Ghz (1Ghz FSB)- 1MB per Core.
if you cannot believe read the article here!
http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2591
if you cannot believe read the article here!
http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2591