Importance of Intel Virtualization Technology for Directed I/O (VT-d)?

Hi,

I'm shopping around for a new laptop for development that is capable of gaming too, so I have mainly been looking at gaming laptops from MSI, Asus, Sager and Alienware. Most of these come with the i7-4700MQ CPU by default, though the Asus G750 uses the i7-4700HQ and some models have an option to upgrade to the i7-4800MQ.

When developing I often work with virtual machines. I notice that the i7-4800MQ and the i7-4700HQ both support "Intel Virtualization Technology for Directed I/O (VT-d)" whereas the more common i7-4700MQ does not. Can anyone explain what difference this will make in practical terms? Knowing that I will be working with virtual machines should I be avoiding the i7-4700MQ in favour of a CPU that supports this?

Edit: I understand that VT-d also requires motherboard support. If it is a feature worth shopping for I'd also appreciate any advice about which laptops' motherboards would support it.

Thank you for your advice!

 

See:
Intel® Virtualization Technology for Directed I/O (VT-d): Enhancing Intel platforms for efficient virtualization of I/O devices | Intel® Developer Zone


Even if you don't currently need the benefits that VT-d offers, the fact that you're using VM's and the possibility that you may need it in the lifecycle of the new system would be enough reason for me to get it.

The other benefit is that with the higher end processors; you'll see up to a 4%-11% increase in your performance too.

If the upgrade price is reasonable (~$100 - $250 - make sure you amortize it over the expected lifecycle of the system), then this is a 'must have' for your indicated workflow.


See:
PassMark - Intel Core i7-4700MQ @ 2.40GHz - Price performance comparison

See:
PassMark - Intel Core i7-4700HQ @ 2.40GHz - Price performance comparison

See:
PassMark - Intel Core i7-4800MQ @ 2.70GHz - Price performance comparison



As a side note; I would be looking at the Asus over the MSI - the MSI's have issues with their performance based on battery charge status.


Good luck.

 

Unless you're actually doing software development within the VM's and need access to the system's hardware you won't ever need it. I think the 4800MQ however is the best performance for the dollar at the moment though, and it includes VT-d. Most laptops that offer those CPU's will support the features.

 

Thanks, tilleroftheearth and HTWingNut. It seems like something I may not end up using, but on the other hand it would be frustrating to buy a machine without it and later realize it would be useful.

The thing that puts me off the MSIs is the single-fan cooling, which some people are finding inadequate. And Alienware is expensive so I am leaning towards either Asus or Sager (though I like the MSI keyboards). I know Asus's quality is reasonable (my current laptop is an Asus), but I could spec out a Sager more closely to my exact requirements. However, I'm not sure about the quality of Sager having never seen or used one.