Triple Head - Dropping FPS

[pfelberg]

Hello,
I´ve come into this situation which I will report to you now. Any comment is appreciated.

What I call Triple Head, is actually a DELL docking device, which is able to work very likely to a Triple Head.
It has 3 outputs. 2xHDMI and 1xDV.
It will not use the HDMI output from computer or notebook. The connection is a USB3.0 cable connected to a USB port.
Differently from the MTH2G, it will not expand the pixel area of a single output, but actually tells windows and Resolume that there are 3 new displays available, according to connected cables.
The docking device then connects to the display devices using HDMI or DV cabling. It supports up to 4K.
Works simple and beautifully in concept, but I am getting low FPS when connecting the device and I would like some more technical explanation, if possible.

Resolume running a simple 1920x1080 composition thru standard HDMI to a single 2nd display, runs at 60 FPS;
Resolume running the same composition thru DELL Docking Device to a single 2nd display, dops to 45/30 FPS;
Resolume running the same composition thru DELL Docking Device to a dual output display solution, dops to 25/18 FPS;

Your thoughts, please.

Thanks,

Paulo

[Oaktown]

What's the GPU on your laptop?

[pfelberg]

Radeon R7 M265

Indeed now I read that there are some new DELL drivers available. Perhaps...

[Oaktown]

I'm assuming the dark is using MST technology, right?

Your card is not a very powerful one so I think the moment you start using multiple outputs, you're taxing it and your FPS drops.

[Zoltán]

the HDMI port on your laptop is most likely connected directly to the gpu, whereas the docking solution is probably some kind of pcie connection, which means the texture has to get off the gpu to get to another display controller.

edit:

The connection is a USB3.0 cable connected to a USB port.

just realized this...

basically you see the same fps drop, like if you were using two graphics cards in a pc.

using an actual matrox triple head off the HDMI would be the best solution.

[Warspite]

Looks like it is not MST hub, but USB videocard.
Forget about this crap - it is good for Power Point Presentation or some simple office work. Usb videocards never work good under heavy load - they do not have power and bandwidth.

[Joris]

basically you see the same fps drop, like if you were using two graphics cards in a pc.

You're seeing a far worse one. These USB devices don't have hardware acceleration.

The only one I've ever seen work with good performance was the Club3D USB3 to DVI dongle. Forget about running 3 displays over USB.