Is it possible to get bootscreen on cMP with a U3818DW or other 3840x1600 res monitor?

[omvs]

One of my colleagues currently uses a cMP 2009 w/ flashed ATI 7950 and the old 30" cinema display. She'd like to upgrade to a bigger screen, and we were originally thinking something like the Dell U3818DW or the LG 38UC99-W with a resolution of 3840x1600.

However I remembered that the ATI 7950 would not give a bootscreen with a normal 4k (3840x2160) screen, and suspecting it probably won't work at 3840x1600 either. Since she uses filevault, not having a boot screen is a big limitation -- not like she needs full res, but needs *something* to come out.

Anybody know of a solution, or a bigger & high res monitor than 2560x1600 that would give a bootscreen with the 7950? Eventually we hope apple will either have a suitable mac pro or mini w/ egpu thats work upgrading to and I expect will solve the problem, but was hoping not to have to wait that long.

Thx in advance...

 

[h9826790]

Just set the monitor setting to DP 1.1 when she really need boot screen, then the 7950 Mac EFI can work properly.

And for daily use, simply boot from the non Mac EFI ROM on the 7950 and leave the monitor setting at DP 1.2 (or above)

 

[haralds]

For the U3818DW the hidden keystrokes are to use the monitor menu to get to the input selector. When DP is selected depress the check button for 10 sec. It will bring up a toggle to enable or disable DP 1.2.

A bit tedious, but it gets easier with time. It's only needed, when you need to get to the boot menu.