[mythtv-users] Combo HD Frontend/Backend/Virtual Machine

[Brian Wood]

On Sunday, August 15, 2010 08:49:58 am Matt Mythtv wrote:
> Hi
> 
> I'm looking to replace my current SD frontend/backend combo with a new
> frontend/backend combo that can handle HD.
> 
> While I'm at it, I'm wondering if I can get a machine fast enough to also
> run Windows under a virtual machine. This will eliminate an old computer I
> have just to run a few Windows only apps.
> 
> I've seen some good prices around for an Athlon II X4 635 (2.9GHz Quad
> Core, 512kb L2 Cache, 0MB L3 Cache). Would this be fast enough for HD
> (either 1080i or 1080p)? Would there be anything left over to run a VM?
> 
> 
> Or is trying to run HD video and a separate VM on the same machine more
> trouble than it is worth?

HD video is not really very resource-demanding, at least not with hardware assist (VDPAU). HD sources present already-
encoded streams to the backend, which then has only to write them to disk. VDPAU-assisted HD playback uses very little 
CPU, many of us use Atom-based systems to play back HD easily.

HD encoding is done by the broadcaster, or in hardware with something like an HD-PVR, no real CPU required, just disk I/O.

As for virtual machines, I don't think the latest Athlons support the hardware assist for virtualization (I might be wrong 
here, but I know only the very latest Opterons do). They will work, but perhaps not as efficiently as a CPU with hardware 
virtualization (VT-x AMD-V). Of course it depends somewhat on which particular virtualization method you use, some will 
not work at all without CPU help. I use VirtualBox with older Opterons and it works quite well.