OpenBSD/amd64 runs on AMD's Athlon-64 family of processors in 64-bit mode. It also runs on processors made by other manufacturers which have cloned the AMD64 extensions. (Some Intel processors lack support for important PAE NX bit, which means those machines will run without any W^X support -- it is thus safer to run those machines in i386 mode).
Note that OpenBSD/i386 also runs on these processors, but in 32-bit mode.
X Window System support is available for most graphics cards, using the X.Org server. As with other free operating systems it is highly recommended that Nvidia cards are avoided since this vendor continues to show tremendous resistance towards releasing information that would allow X.Org to support their hardware properly.
The only major shortcoming at this time is that the kernel debugger ddb is somewhat poor.
All versions of the AMD Athlon 64 processors and their clones are supported.
Starting with OpenBSD 3.6, OpenBSD/amd64 supports most SMP (Symmetrical MultiProcessor) systems. To support SMP operation, a separate SMP kernel (bsd.mp) is included with the installation file sets.
New hardware is constantly being released, some of which may lack support. Your donation of time, hardware, or documentation can accelerate this support!
The latest supported OpenBSD/amd64 release is OpenBSD 5.5. Here are the OpenBSD/amd64 5.5 installation instructions .
Snapshots are made available from time to time, in this location as well as in a few mirrors. Here are the OpenBSD/amd64 snapshot installation instructions as well.
There are several installation media provided: