Enlarge “virtual Screen” when screen-sharing a headless Mac?

I found something called a "DVI Dummy Plug" that possibly(?) would fool the Mac Pro into thinking it has a monitor attached. It claims a resolution of 2560X1600. Apparently, they are used to allow the GPU to be used as another processing unit — mainly for cryptocurrency mining, but perhaps it will work for my purposes.

I would be grateful for any comments about this... they are quite inexpensive (<$10), so I will order one and try it out.

I received the Headless Mac Video Accelerator and it works pretty well — I'm generally satisfied. However, it advertises that it will display up to 1920x1080 and I only get 1680x1050. I use a ATI Radeon HD 5770 1024 MB GPU on the remote Mac Pro (5,1) which supports 1920x1080 (up to 3840x216), so not sure why I can't get the higher resolution. The display is snappy, so it is obviously benefitting from the GPU. I am displaying the remote Mac on a 2560x1440 iMac Pro screen (or the attached 2560x1440 LED Cinema Display), so these screens should be adequate for a 1920x1080 virtual screen.

Not sure if this is relevant, but the 1920x1080 resolution wasn't available until I downloaded the "Display Menu" app from the App Store and installed on the headless Mac Pro.

Anyone have an idea why I can't get the full 1920x1080 resolution?

Grant,

It says "Unknown Display" and it shows 1280x1024 under the "Scaled" Resolution option under "Resolution." It doesn't show any resolution when "Default for Display" option is selected, but both appear exactly the same on the iMac.

There are no other resolution options shown and holding "Alt" (or control), doesn't do anything.

Yes.. I have the real graphics card installed in the Mac Pro, so there is a place to put it. I occasionally attach a monitor to the Mac Pro, but usually just run via screen sharing to complete various tasks on outdated software. I have placed my 32 bit Aperture library there (mostly as an archive) and access it through my iMac Pro as needed (not to complete serious work). Although I have transitioned to Lightroom, I still find it useful to refer to Aperture occasionally.

I guess I will see if it works with Intel processors... they advertise that it works with Windows or MacOS, so I am hopeful. I am still not sure if it will allow me to run the screen sharing at higher resolutions, though.

I should have mentioned that I am running 10.10.5 (Yosemite) on the Mac Pro and 10.13.6 (High Sierra) on the iMac Pro.

Awesome! I have a Mac Pro 5,1 also.

I saw another type on Amazon, but it looked pretty sketchy. Cancelled the Amazon order and ordered the one you linked to.

Thanks!

Never-mind! It seems to be working perfectly now!

I get the full 1920x1080 resolution.

Nice!