MP 1,1-5,1 Resolution oddness with flashed 7950

[imrazor]

I recently dropped a flashed PC Sapphire HD 7950 3GB into my cMP5,1. Oddly, it will only drive my Samsung 4K display at 1080p when running Mojave. However, if I reboot into Windows 10, it has no problem operating at 2560x1440.

I found that if I used ResXtreme, I could force the monitor to work at 1440p, but the fonts were markedly blurrier than on Windows. So two questions:

1) Why won't Mojave work at 1440p without coercion?

2) Is there any way to fix the blurry fonts in macOS @ 1440p?

 

[Nguyen Duc Hieu]

Your issues are described in this post already.

MP5,1: What you have to do to upgrade to Mojave (BootROM upgrade instructions thread)

Please fully read this first post, you will probably find that you have one or more problems described into the various notes below. Mojave will only install if you have upgraded your BootROM to the current release and your Mac Pro have a Metal capable GPU*. If you are trying to install Mojave...

forums.macrumors.com

 

[h9826790]

I recently dropped a flashed PC Sapphire HD 7950 3GB into my cMP5,1. Oddly, it will only drive my Samsung 4K display at 1080p when running Mojave. However, if I reboot into Windows 10, it has no problem operating at 2560x1440.

I found that if I used ResXtreme, I could force the monitor to work at 1440p, but the fonts were markedly blurrier than on Windows. So two questions:

1) Why won't Mojave work at 1440p without coercion?

2) Is there any way to fix the blurry fonts in macOS @ 1440p?

You should choose 1440P HiDPI, but not 1440P.

All 2x Scale options in ResXtreme are the HiDPI resolutions.

 

[imrazor]

@Nguyen Duc Hieu The Boot ROM version on my cMP5,1 is already at 144.0.0.0.0

@h9826790 In ResXtreme the only scale options available are 1x, NOT 2x.