The idea of an external graphics card seems a little far-fetched, but at least two companies are actively developing housings for PCI-e cards using the MiniPCI-e interface on modern laptops.
The Possibility of Gaming Graphics on a Laptop
While there is plenty of space for additional cards and the required cooling inside the majority of PC cases, the same sadly isn’t true for laptops. Unless you’re able to invest in a very high-end device, hardcore gaming with the full graphics experience is going to be difficult to achieve on a notebook computer.
To solve this, several graphics cards manufacturers have begun designing and releasing external video card enclosures – a graphics card in a box – that can be plugged into a notebook computer and used for gaming.
However there are various physical limitations preventing this sort of endeavor from ever having any mainstream success.
External Video Card Enclosures – the Limitations
The main perceived problem with external video card enclosures is that the presumed means of connection – USB – doesn’t possess enough bandwidth to offer a suitable alternative to the low-fi graphics found inside most laptops.
USB 2.0 offers a bandwidth of 480Mbit/s, while the now abandoned AGP graphics card specification could supply 8.533 Gbit/s. Conversely the current graphics standard, PCI-e, offers at least 16 Gbit/s.
With this amount of graphics data processing flowing through a USB connection, the graphics would be pretty slow, defeating the object of having a top of the range graphics card in a box connected to your laptop.
As such, an alternative connection is required.
(Figures via http://en.wikipedia.org/wiki/List_of_device_bandwidths)
Produced by VillageTronic (www.villagetronic.com), the Vidock range of external video card enclosures supports the ExpressCard interface on modern laptop computers (the replacement for PCMCIA/CardBus which is derived from PCI-e) and PCI-Express cards.
Various models of the Vidock are available, each designed for PCI-Express graphics cards and offering variations on the size of card you can use. There is even a model that allows for 225w graphics cards to be housed and powered for real high-end portable gaming!
Despite the success of the Vidock, however, it remains an expensive solution, with the cheapest housing costing $199. There are also compatibility issues with various Apple MacBooks.
A Hope for the Future?
Following an initial design proposition in 2006, ATI discarded the idea of an external housing for a graphics card, presumably for the reasons mentioned above.
However ATI has since been purchased by AMD, who have a whole new take on the concept thanks to the introduction of MiniPCI-e. The slimmed down version of PCI-Express enables data transfer comparable to the Vidock device.
The ATI XGP comes housed in a device known as the AMD 5000 Series Mobility External GPU, which is equipped with DVI and HDMI connectors, three video out ports, two USB 2.0 ports, and a hefty 35W power adapter. However there is as yet no word on a formal release date.
While AMD’s device might prove to be the solution of choice thanks to the strength of the brand name, in the meantime the Vidock is the way to go.
(Images via corresponding links)