Re: Hardware recommendation request

[Christoph Egger <Christoph_Egger%gmx.de@localhost>]

On Thursday 28 August 2008 17:32:46 John Hayward wrote:
> I can tell I did not make part of my request clear.
>
> >>     What chip and motherboard would work best with NetBSD-Xen to support
>
>              ^--- here I was asking about AMD/Intel chips

Regarding paravirtualization, it does not matter if you have AMD or Intel.
Regarding hardware-virtualization, there is a big difference:

- AMD provides real mode in hw, Intel does not.
  => Instruction execution in real mode is emulated in software on Intel CPUs
         by the hypervisor
  => Some guest OS's have boot problems on Intel CPUs

- AMD Barcelona/Phenoms feature the "Rapid Virtualization Indexing"
  => HVM guests *with PV drivers*  can run up to 90-97% of native performance
  HVM guests w/o PV drivers are slower due to IO overhead, but are still up
  to 80% of native performance
  AMD K8 and Intel CPUs don't have this feature, there you get about
  60 - 70% of native performance
  For more performance on Intel CPUs you have to wait for Nehalem
  which will have this "Rapid Virtualization Indexing" (or however Intel will
  call this)


Christoph