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What It Takes to Connect an External GPU to a MacBook

By Wesley Fenlon

Short answer: A whole lot of stuff.

What are Macs historically bad at? Gaming. And what are most laptops especially bat at? Gaming. Put the two together, and, well, most MacBooks--especially MacBook Airs--are low down on the list of good portable gaming computers. That's why everyone perked up earlier this week when a story went around about connecting a GPU to a scrawny 11-inch MacBook Air. The obvious question is: How? The answer: Thunderbolt.

And, well, about $250 worth of other stuff. A forum post on Tech Inferno lays out the whole process and the results, which were performance gains between 5-7x over the Air's integrated GPU. First off, this isn't an entirely new idea--we even looked at an external Thunderbolt GPU built by MSI at CES in 2012. For some reason, though, this technology has never made it to market. Intel hasn't officially certified GPUs for use via Thunderbolt. But that doesn't mean they won't work.

PHOTO CREDIT: FLICKR USER LEMONPIXEL VIA CREATIVE COMMONS

First comes the shopping list. Larry Gadea, who posted this whole setup on Tech Inferno, recommends the following parts:

  • A Thunderbolt cable
  • A graphics card, preferably Nvidia. The article notes "on AMD cards, internal LCD rendering won't be possible without using something like Lucidlogix Virtu."
  • A 450 watt power supply for the video card. You may need more or less power, depending on the card you use.
  • The Echo ExpressCard Pro, which costs about $150. This card converts Thunderbolt into the ExpressCard interface. In the process Thunderbolt's 10 Gb/s speeds are reduced to 5 Gbps. There are faster options, but they cost up to $350 dollars, and aren't as user-friendly.
  • The BPlus PE4VL v2.1, which costs about $70. This adapter converts ExpressCard to PCIe.
  • DIY eGPU Setup, which costs about $25. This piece of software allows Windows 7 bootcamp running on a MacBook to properly accept a signal from the video card.

Once you have all that equipment, the tricky stuff begins. The equipment has to be booted up in a specific order, there's tons of exposed wiring, and getting Windows to recognize the hardware requires a little messing around in config files.

Photo credit: Larry Gadea

The tutorial also notes that performance is better when routing video to an external monitor plugged into the laptop. Playing The Witcher 2 on the laptop's monitor, for example, using an Nvidia GTX 570 improved performance by 4.9x. Plugging in an external monitor delivered 6.5x performance over the built-in Intel HD 5000 GPU.

This is a messy solution, but it does work. And hopefully it will get easier. Another forum poster notes that SilverStone has built an external GPU case which integrates a 450W power supply and cleans up all the messy cabling. It's set to cost $250, but it has to pass Intel's Thunderbolt certification. And since Intel has yet to certify any external GPU equipment, it's hard to say whether SilverStone will get the chance to make external laptop GPUs practical.