by Andrew Cunningham on 8/3/2011 2:00:00 PM
Posted in Thunderbolt , graphics , GPUs

Village Instruments CEO Hubert Chen wrote an open letter to Facebook last week, attempting to gague customer interest in an external PCI Express graphics card enclosure for Thunderbolt. He said that the company would begin development on such a device if 50 people left a comment indicating interest - as of right now, the letter has well over 300 comments, and Chen confirmed in a follow-up note that development on the peripheral would begin soon.

Village Instruments currently makes the ViDock, a graphics enclosure that uses the ExpressCard interface - the new Thunderbolt ViDock will probably be similar in construction to the current model. Performance of the new Thunderbolt device should improve considerably, since Thunderbolt gives devices 10 Gb/s of bandwidth to work with, while ExpressCard devices can only use about a quarter of that.

The Thunderbolt ViDock, when it's released, will be a boon to thin-and-light laptop owners who want good battery life and weight while they're on the road, but good graphics performance when they're at their desks.

Source: Facebook 

Thanks Sean for the tip!

Something usefull? by haukionkannel on Wednesday, August 03, 2011
This sounds like a usefull Thunderbold usage. Does some one remember how much bandwidth normal PCI Express does offer?
It will be interesting to see how near normal performance this would offer.
haukionkannel
RE: Something usefull? by Andrew.a.cunningham on Wednesday, August 03, 2011
I think PCIe 2.x gets 8 GB/s either way in an x16 slot, and PCIe 3.x will up that to 16 GB/s. Seems like we could finally start getting close!
Andrew.a.cunningham
RE: Something usefull? by Zok on Wednesday, August 03, 2011
Thing is, thunderbolt is 10 Gb/s, not GB/s. So, thunderbolt is 1.25 GB/s, thus able to handle a 4x electrical lanes of PCI-E 1.x (5x doesn't exist) or 2x electrical lanes of PCI-E 2.x.

Of course, x16 graphics cards will still work, but will only have a 1/8 of the available bandwidth.
Zok
RE: Something usefull? by superunknown98 on Wednesday, August 03, 2011
Depending on the implementation, Thunderbolt can provide up to four channels of bi-directional data. So at 10Gb/s per channel per direction, you end up with 80Gb/s. That would be 10GB/s in total, however i'm not sure if one device can use all four channels.
superunknown98
RE: Something usefull? by Zok on Wednesday, August 03, 2011
You do have a point, but I share your doubt on whether or not a device can properly communicate over the bonded channels.

I can't recall, but doesn't DisplayPort occupy 2 of the 4 channels in the MBP/iMac controller and 1 of the 2 channels in the MBA controller? Or are their connections separate?
Zok
RE: Something usefull? by Wolfpup on Thursday, August 04, 2011
I want to say that...okay, the CPU has 16 channels total ('cause Intel's skimping out lately), and half are for the GPU, four are for the display part of Thunderbolt?
Wolfpup
RE: Something usefull? by JasonInofuentes on Thursday, August 04, 2011
So, I need to do my research on this, but the point of the Thunderbolt chip is to actually mux the data channels for transport down the wire, meaning the devices connected via TB will be able to implement more than a single lane, and up to the whole load. So, while a lane is typically reserved for DisplayPort, if a discrete graphics card is being used there will not be any load on that reservation so it should free up it's bandwidth. We'll follow-up on this.

Jason
JasonInofuentes
RE: Something usefull? by Andrew.a.cunningham on Wednesday, August 03, 2011
That lowercase B gets me every time. Article updated for accuracy. Let my comment stand as a testament to my error.
Andrew.a.cunningham
RE: Something usefull? by FITCamaro on Wednesday, August 03, 2011
Agreed. I would love to be able to have an external graphics card. We should've had this technology years ago. How hard is it to implement a mobile chipset with a full PCI-E 16x port that has an external plug. Then you get the GPU of your choice and plug it in using a special enclosure. Some of tried in the past but its always been bad at best.

Many laptops today have great CPUs and lots of RAM, but lacking graphics. I don't even care if its hot swappable, just give me the option.
FITCamaro
RE: Something usefull? by A5 on Wednesday, August 03, 2011
"We should've had this technology years ago."

"Some of tried in the past but its always been bad at best."

There's your answer. Turns out that it's hard to do. I don't think it'll really be practical until the optical version of Light Peak is out.
A5
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