Official torrent from the linux mint website.
Introduction to Linux Mint 8 x64:
This x64 edition of Linux Mint 8 is almost identical to the Main Edition but compiled for 64 bit processors (Intel Core 2 Duo, Intel Core 2 Quad, AMD Athlon X2 64 and all x86-64 compliant processors). It comes with all the improvements featured in Linux Mint 8 Helena Main Edition.
After the ISO is downloaded verify the MD5
Burn the ISO at low speed and enjoy Linux Mint 8.
An X86_64 64 bit processor (Intel Core 2, AMD X2 64, etcâ€¦) .
A minimum of 512MB of RAM is recommended. Once installed the system works fine with as low as 256MB RAM. The installation process deals with 2.5GB of data compressed on a 700MB CD and it can hang or fail on systems with less than 512MB RAM. If you have between 256MB and 512MB RAM you may have to try to install several times.
Size: 686MB LiveCD