We have some bad news for you today, at least if you were hoping to use a discrete graphics card combined with Thunderbolt for your CustoMac. Via the grapevine we’ve heard that both Asus and ASRock has been denied Thunderbolt certification by Intel for their external pass-through solution which would’ve allowed a discrete graphics card to be used in combination with Thunderbolt. Intel is currently the sole manufacturer and certifier of Thunderbolt controllers and as such, if you don’t meet or exceed Intel’s specification, then you won’t get certified and in turn, your product can’t carry the Thunderbolt logo. In this case it appears to be more of a political issue than an actual concern about Asus and ASRock not meeting Intel’s standard, as Intel is clearly using Thunderbolt as a means of pushing its integrated graphics solution. In a Windows environment, currently the only approved method of interfacing a discrete graphics card with the Thunderbolt ports on a motherboard – be it in a notebook or a desktop – is by using graphics switching software such as LucidLogix’s VirtuMVP software or Nvidia’s and AMD’s proprietary solutions used in notebooks. This way the graphics signal is fed from the discrete card via the internal PCI Express bus, rather than via an external DisplayPort cable, as is the case in Asus’ and ASRock’s implementations which Intel now has declined as not meeting the Thunderbolt standard. This is at least so far bad news for CustoMac users, as either solution would’ve made it much simpler to use a discrete graphics card with the Thunderbolt/mini DisplayPort connectors on the motherboards. It will be interesting to see if the two companies can make some kind of deal with Intel to allow this implementation in the future, or if they’ll simply ignore the certification process and still sell their products, although the latter option doesn’t seem all that likely. We will follow this topic closely and see how things develop, but we can’t see Intel letting up on its strict certification process any time soon, as the company wants you to use their graphics over a discrete card, despite the relatively poor performance that Intel’s HD graphics offer compared to a discrete card.