This could be a DNS issue. See this question here http://serverfault.com/questions/511072/troubleshooting-network-latency
If your internet provider has configured a loop on their network, then you will get extremely slow performance.
Some things you can try to alleviate it:
Check what your DNS settings are set to in Mac / Chrome vs Windows
Change your DNS settings to a different DNS server
Check if your computer has the same problem on a different network (Take computer to friends house)
Check if you can access the website with curl
- Check if you can access the website with telnet
telnet www.foo.com 80
GET / HTTP/1.1
- Install Wireshark and run a network dump on Mac to a network dump on Windows.
Recently at my job we found only the linux computers had trouble accessing some websites, turned out that linux was much less forgiving than windows when packets had invalid time stamps. Our internet provider had to make some changes on their network to alleviate the issue.