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View Full Version : is there a performance impact due to Display Link?


saz25
03-12-2013, 03:22 AM
Hi,
I just ordered an HP Pavilion dv6t i7 laptop.
I haven't purchased a USB 3.0 dock yet as I am still researching the various brands/models.

My first question is this. Is there a performance or quality difference when the monitor is being driven by a USB 3.0 DisplayLink device as compared to a direct connection to the laptop's video/graphics subsystem?

Does this negate the features and performance benefits of the graphics card?

Doesn't DisplayLink render everything in software and wouldn't that degrade overall performance?

I really want to be able to treat the laptop as a virtual desktop, where I'll leave it closed with a connected external keyboard, mouse, and monitor when docked.

Just curious.
thanks,
Steve

Wim
03-12-2013, 12:50 PM
There is some system overhead, as we need to encode the pixels and send them over USB. The CPU used will increase, the more that is changing on the screen, but it will not max out on a modern PC.

I use a Dell Core i5 machine every day and have 4 USB displays connected through a DL-3900 dock (2 from the dock, and 2 through adapters). I notice no performance difference between the USB screens or directly connected, however I'm not playing 3D games at work, which may not perform as well as a directly connected display to the graphics card. I've attached a picture to show my set up. My laptop is off on the right with the display switched off.

Wim

saz25
03-12-2013, 03:50 PM
There is some system overhead, as we need to encode the pixels and send them over USB. The CPU used will increase, the more that is changing on the screen, but it will not max out on a modern PC.

I use a Dell Core i5 machine every day and have 4 USB displays connected through a DL-3900 dock (2 from the dock, and 2 through adapters). I notice no performance difference between the USB screens or directly connected, however I'm not playing 3D games at work, which may not perform as well as a directly connected display to the graphics card. I've attached a picture to show my set up. My laptop is off on the right with the display switched off.

Wim

Thanks for the response and image. Looks great.

A couple of related questions.

I recently ordered an HP laptop Pavilion dv6t-7000 with Intel i7 and nVidia video. While the unit isn't due to arrive for about 2 weeks, I'm looking for a docking station/port replicator.

I've read about problems with DisplayLink and nVidia. Should I expect those problems? How to avoid them?

Are there any known issues with the HP 3005pr USB 3 replicator ? Does it fully support Win7 64 bit? I am also considering the Targa U3 unit. But I am certainly open to others.

Do all the USB 3.0 docking units use the same DisplayLink chips, so they are all basically the same except one unit may have more ports than another?

I'd like to be able to leave the laptop closed when at my desk so I can use an external keyboard, mouse, and monitor. I see that yours, in the image, is open.

Does HP make their own USB 3.0 device (3005pr) or does a 3rd party make it for them?

I've read so many stories on various forums regarding these things.

Any suggestions as to which unit is more reliable than others ?
I need to order something soon, but I don't want head aches when it arrives.

thanks in advance for your help,
Steve

luiset83
03-25-2013, 08:24 PM
Thanks for the response and image. Looks great.

A couple of related questions.

1) I've read about problems with DisplayLink and nVidia. Should I expect those problems? How to avoid them?

2) Are there any known issues with the HP 3005pr USB 3 replicator ? Does it fully support Win7 64 bit? I am also considering the Targa U3 unit. But I am certainly open to others.

3) Do all the USB 3.0 docking units use the same DisplayLink chips, so they are all basically the same except one unit may have more ports than another?

4) I'd like to be able to leave the laptop closed when at my desk so I can use an external keyboard, mouse, and monitor. I see that yours, in the image, is open.

5) Does HP make their own USB 3.0 device (3005pr) or does a 3rd party make it for them?

6) Any suggestions as to which unit is more reliable than others ?
I need to order something soon, but I don't want head aches when it arrives.

Without directly answering all the questions, my main advice is order from a reputable retailer that advertises a good return policy -- for example, Wal-Mart sells the Targus ACP71USZ, so you could return it in store if need be. Buy.com (Rakuten now) also sells that one and the HP 3005pr. J&R also sells the 3005pr. All of these retailers have very lax return policies in case they do not work out for your particular hardware/software combination.

Now a direct answer:

1) Maybe? Stick to the NVIDIA drivers that are maybe 1 revision behind the current ones if the latest don't work

2) I'm not aware of any issues in my case, except for some slight lagging every once in a while with mouse movement. I experienced this both on Win7 and Win8, with both the targus and the HP models... so it must be a DisplayLink driver issue.

3) They are very similar, minus any particular features they differ with.. they use the same chipset and drivers.

4) I believe I saw mentioned that the laptop screen must be open in order for the other monitors to be active.

5) No idea, presumably it's made by HP, but I wouldn't be looking for support there, mainly just here.

6) Having tried the Targus and HP, both units seem to behave identically, with the exception that the HP supports higher than 1080p resolutions over DisplayPort (DP)

wangna
06-14-2013, 09:11 AM
I haven't purchased a USB 3.0 dock yet as I am still researching the various brands/models.





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