[mythtv-users] Virtualisation in the home network -- ready for mainstream?

Matthew McClement mythtv at macker.co.uk
Fri Sep 4 14:07:24 UTC 2009


Jon Whitear wrote:
> On 04/09/2009, at 1:50 AM, David Schlenk <mythtv at schdav.org> wrote:
*snip*
>> 
>> AMD: Yes unless it is old or is particularly cheap Sempron. Budget
>> virt boxes is pretty much the only place AMD wins over Intel right
>> now, as Intel uses it to segment their market.
> 
> Judging by intel's CPU comparison (ark.intel.com/vtlist.aspx) if I
> want to go quad core with VT-x, I'm looking at a core 2 8400
> (~AU$230) or one of the 9xxx aeries. Is there much difference other
> than cache size and speed?

Be careful with the 8400. Only R0 steppings include VT-x, previous
steppings didn't. Intel added VT-x support to a number of their CPU's
after it was revealed that Windows 7's XP mode would require VT-x.

> The AMD Phenom II 810 is around the same price as the 8400.
> 
> The intel chips won't have VT-d. I can't tell if AMDs Iommu is a 
> function of the CPU, the chipsets or both. Should I care?

VT-d is always a function of the chipset. At least currently, things may
get a bit muddled when Westmere/Sandy Bridge comes around.

In Intel land, The Xeon 5400(and up) and 3200/3210(and up) chipsets have
VT-d as well as the Q35 and Q45(check the manual of the motherboard
though, as I believe it's something that has to be specifically
implemented by the manufacturer and might also have some ICH
restrictions). For i7, X58 *does* support VT-d, but only the most recent
stepping. Figuring out if your motherboard has the right stepping might
be a bit of a task however.

AMD doesn't have an IOMMU on any of it's released chipsets. That's due
for the 800 series which was meant to be out this year but I've not
heard much about it recently.

Whether you need VT-d is debatable however. It's main use seems to do
PCI passthrough. If you have PCI devices that have no alternative(e.g.
HDHomerun), then it has some value.

Matt


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