VT-d support on Z77 boards

[mikewse]

It has been mentioned previously that Asrock supports VT-d (virtualized I/O) on most Z77 motherboards.

But according to Intel's spec sheet:
ARK | Intel® Z77 Express Chipset (Intel® BD82Z77 PCH)
the Intel Z77 chipset doesn't support VT-d.

How is it then possible for the motherboard to support it?

[profJim]

There are probably other Intel z77 chipsets that support VT-d.
The chipset in the link you provided only supports pci-e 2.0.
The cpu and motherboard must both support VT-d.
The Ivy Bridge and Sandy Bridge K model processors do not support VT-d.
A web search using: ivy bridge vt-d motherboard support should provide more information.

[mikewse]

Ok, so let me put it this way:
The Asrock Z77 Extreme4 has VT-d support.
What version of the Z77 chipset does it use?

[synack]

Its the northbridge (that is now "ON DIE" with Sb and IB) that does the vt-d not the chipset. You need to find a compatible CPU and a motherboard that has been configured to allow/enable the on CPU feature.

[mikewse]

Thanks, this sounds reasonable. Isn't it strange though that the Q77 chipset is speced as VT-d compatible while the Z77 isn't?
ARK | Intel® Q77 Express Chipset (Intel® BD82Q77 PCH)

I've seen mentions of an Intel vt-d verification tool that tests whether full vt-d support is available (but haven't found a download).
Have you verified your Z77 boards with this tool?

[synack]

I have a K processor, so my processor doesn't support it. besides, I have no reason to care about vt-d. I do not need to pass through any hardware through any of my VMware servers. personally or professionally (I professionally manage a 8 host enterprise esxi cluster with 400 guests on them. personally 1 host with 5 guests)

vt-d breaks advanced features in vmware, for instance vmotion. (which is one of the best features ever). The limitations imposed by vt-d negate the purpose of having virtualization these days. and seriously though, who needs to pass though a gtx 680 to a single guest? lol.

mainly this is why support for vt-d is weak, there is very little desire to have it. Those who do need it,need it for very niche applications. Ones that can be solved by just not bothering with Virtualization for that one particular need.

I'm not saying you shouldn't use it, but that is the reason why it is difficult to find any information about a seemingly miraculous feature. And why it's so hard to find out what does and does not have it.

I suspect that it's an error on Intel's part to list the q77 express with vt-d = "yes", as a Q77 is essentially an H77 with vPro. H77 also lists vt-d as "no"
I've never seen a verification tool, but then again, I've never looked for one. I suspect it'll be one of the main VM OSs like citrix, vmware or KVM that has the tool.

[parsec]

Intel now tends to separate product features into groups, and there are few if any individual components that have all of them. For example, if you want the "K - Unlocked" CPU to OC, you must get a matching chipset board, but then you lose features like Vt-d, and many of the other more enterprise oriented types. Go in the other direction for the enterprise oriented features, and you lose the ability to OC and get only one SATA III port on the board. The reason may be simply marketing and the needs of the customer, but that split might just benefit Intel economically too.

[kpo6969]

Ok, so let me put it this way:
The Asrock Z77 Extreme4 has VT-d support.
What version of the Z77 chipset does it use?

If you update to the latest bios (P2.70) it is no longer supported. P2.50 and lower it should.

[mikewse]

mainly this is why support for vt-d is weak, there is very little desire to have it. Those who do need it,need it for very niche applications. Ones that can be solved by just not bothering with Virtualization for that one particular need.

Thanks for the insights. I'm building a new system and as I'm going to go deep into virtualization I'd like to keep my options open and get a system that can do VT-d. Maybe I won't use it in the end, but rather be safe than sorry.

If you update to the latest bios (P2.70) it is no longer supported. P2.50 and lower it should.

That's very interesting, and confusing :-P
Any insights why?

[mikewse]

There seems to be several different possible answers to this question.
Can we have some official word from Asrock staff in this matter?