This is been a huge Public Relations time for Intel, 3 huge companies have announced switching to and or back to Intel CPU’s over the past year.
So, the question is why. The magic number is 4. Both AMD and Intel are pushing their quad core cpu’s. AMD’s Barcelona is consider a true quad core cpu. Intel’s quad core is argued that it isn’t a true quad core, because it is technically 2 duo cores on the same die.
Lets look at the count:

Companies switching to or including AMD:
1. Dell, site:www.dell.com
Companies switching to or including Intel:
1. Google, site:www.google.com
2. Apple, site:www.apple.com
3. Sun Microsystems, site:www.sun.com
What does this mean? AMD has made announcements about their chips being faster for virtualization. According to ZDNet: (Read Complete Article)
Barcelona has specific features to deal with some of those performance issues, Ben Sander, a principal member of AMD’s technical design staff, said in a speech on Tuesday at the Fall Processor Forum.
AMD and Intel are vying for share in the x86 server market. Intel’s Xeon chips were the first to provide some hardware support of virtualisation, but AMD’s newest processors now also support it.

Sources:
http://www.theinquirer.net/default.aspx?article=37230
http://news.zdnet.co.uk/hardware/0,1000000091,39285641,00.htm
http://news.com.com/2100-1014_3-6153431.html
http://www.zdnetasia.com/news/hardware/0,39042972,61984834,00.htm
http://www.hpcwire.com/hpc/1225351.html