by Kristian Vättö on 9/29/2011 11:27:00 AM
Posted in GPUs , Displays , USB 3.0 , DisplayLink

Although IDF 2011 ended two weeks ago, not everything has been covered yet. One thing we missed was DisplayLink's announcement of their first USB 3.0 video adapters. There will be two models: DL-3500 and DL-3900. The first one is a regular USB to HDMI adapter and supports resolutions of up to 2048x1152, meaning that it's sufficient for all today's HDMI monitors. It doesn't seem much different from what USB 2.0 video adapters offer, but the added bandwidth should help with more intensive content, such as videos. 

The second one, DL-3900, is a bit more than just a video adapter. It's more like a docking station since the actual chip supports DisplayPort, VGA, DVI and HDMI. On top of that, it supports networking and can act as a USB 3.0 hub. Resolution support is up to 2560x1600, or two 1920x1080 displays. DisplayLink only manufactures the chips (just like AMD and NVIDIA for example), so the final configuration is dependent on the OEM. At IDF, DisplayLink showed off a prototype with DVI, HDMI, two USB 3.0 ports and an Ethernet port. Both adapters support multi-channel audio and 3D video playback.

DisplayLink has not revealed official pricing. SemiAccurate is claiming about $80 for the USB to HDMI adapter and $150 for the dock. DisplayLink lists only "available soon" on their site, so availability is unknown as well. It's again good to note that DisplayLink only manufactures the chips - pricing and availability depend on the OEM. 

While USB 3.0 can't deliver the same bandwidth as Thunderbolt, it's still capable of 5Gb/s (theoretically), which is ten times more than USB 2.0. That should be enough for most users, although it will be interesting to see how the DL-3900 performs with multiple devices. It's evident that there is a lot compression going on in order to provide 2560x1600 over USB 3.0 in the first place. Apple's Thunderbolt Display (our review) is definitely an interesting concept and DisplayLink takes a similar approach with DL-3900. Samsung also introduced Central Station (our analysis) a while back, which is an equivalent docking station concept. 

Source: DisplayLink, DisplayLink, SemiAccurate

Finally... by Tanclearas on Thursday, September 29, 2011
The DL-3900 is what I've been looking for. We have quite a few laptop users that want docking stations. We end up having to order the model-specific docking stations, most of which are over $150. USB 2.0 docking stations are just painful.

Bandwidth shouldn't be too much of an issue. Most of the monitors in the offices are 1920 x 1080.
Tanclearas
Compression? by barich on Thursday, September 29, 2011
USB 3.0 is faster than AGP 4X. I'm not sure why you'd need any compression.
barich
RE: Compression? by Kristian Vättö on Thursday, September 29, 2011
AGP x8 is good for up to 8.5Gb/s, which is 3.5Gb/s more than USB 3.0.
Kristian Vättö
RE: Compression? by Tanclearas on Thursday, September 29, 2011
2560 x 1600 x 24 (bit) x 60 (fps) = 5898240000 bps, or nearly 6Gbps. That is assuming a software-based video driver outputting the frames over USB.
Tanclearas
RE: Compression? by IvanAndreevich on Tuesday, October 04, 2011
All the data is loaded to the graphics memory which is an order of magnitude faster. Try gaming at 2560x1600 on integrated graphics where the bandwidth is limited by system RAM and graphics bus, and you'll understand why you need compression :)
IvanAndreevich
USB generates CPU interrupts by ChristophWeber on Thursday, September 29, 2011
This is a nice stopgap solution, but I'd be weary of CPU load. USB generates a lot of CPU interrupts because of its lack of direct memory access.
ChristophWeber
RE: USB generates CPU interrupts by The_Countess on Friday, September 30, 2011
I'm not sure about this but with HDD/SSD's usb3.0's CPU use was only 0.5% higher then that of Sata, getting similar transfer speeds, and far less then USB2.0 which got lower transfer speeds.
The_Countess
RE: USB generates CPU interrupts by Filiprino on Friday, September 30, 2011
Bulk transfers do not generate so much interrupts.
Filiprino
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