Hitchhiker's Guide to Openbsd

12.1.8 - How do I activate my crypto accelerator card?
Supported crypto accelerator hardware, such as the 
hifn(4)
based cards will "just work" when installed in 
an OpenBSD system. No activation or other configuration is needed. 
The overhead of talking to one of these devices will sometimes negate much or all of the benefit of 
offloading the processor of the crypto tasks. Your results may vary widely depending on the task you 
have to accomplish. 
12.2 - DEC Alpha
[nothing yet] 
12.3 - AMD 64
12.3.1 - Can I run OpenBSD/amd64 on my Intel P4?
In the case of many recent processors, the answer is "yes". Unfortunately, trying to find out which Intel 
processor variations do and which do not properly support the amd64 instruction set is difficult. It is 
usually easier to just try it and see if it works. 
12.3.2 - Can I run my i386 binary on OpenBSD/amd64?
No. 
OpenBSD/amd64 is a totally separate platform from OpenBSD/i386, and at this point, no binary 
compatibility is provided. As OpenBSD encourages open source applications, there is not much interest 
in binary compatibility across platforms with developers. 
Note that the OpenBSD/amd64 and OpenBSD/i386 boot loaders will load each other's kernels, making it 
easier to reinstall a system with the "other" platform. However, it has to be a complete "wipe and 
reinstall" operation -- left-over binaries from the "previous" installation will most likely make your life 
unpleasant. 
12.3.3 - Is it always better to run OpenBSD/amd64 on processors that 
http://www.openbsd.org/faq/faq12.html (5 of 12)9/4/2011 10:02:18 AM

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12 - Hardware and Platform-Specific Questions
support it?
Not always. 
There are a number of reasons one may desire to use OpenBSD/i386 over OpenBSD/amd64, even on 
hardware that supports amd64 code: 
●
Need for i386 binary (or other OS) compatibility. 
●
Need to run applications that are not "64 bit clean". 
●
Need for ability to move disks to another machine that isn't amd64 capable 
●
For some applications and on some hardware, OpenBSD/i386 may outperform OpenBSD/amd64. 
Relatively few people will ever experience this, and work is on-going to eliminate as many of 
these situations as possible.