3440X1440 over HDMI

blueteq

I upgraded from LG Ultrawide to the predator X34P to get better refreshrate, which on my PC running 1080Ti looks amazing.. 
However my work computer which is a MacPro with GT210 card I cannot get more than 1080p with black side bars connected over HDMI to the X34P. 

LG over same HDMI cable worked perfecrly fine with ultrawide at 3440X1440, which makes me wonder if its a setting or something I am missing. 
I will be using the monitor 60% on Mac to work (so I can pay for the) 40% gaming I will be doing on the monitor.

I tried PRAM reset and SMC Reset on MacPro, I installed Custom resolution utilities like CSCREEN but cannot get the ultrawide working. 
Also had a Quadro NVS295 and ATI Radeon card installed, they boot fine but same 1080p Limit. 

Any help would be appreaicted as it was a LOT of money to drop on a display... 

staticfade

Actually, I ran into the same issue with HDMI input on this monitor.  Although the spec is HDMI 1.4 which can handle 4K resolutions, the port on this monitor will only display 1920x1080.  I have hooked up my PC which uses the DisplayPort at 3440x1440 and then plugged in the same PC to the HDMI port using a new HDMI cable (Audioquest) and the max resolution in Windows 10 is 1080p.  I then tried connecting my MacBook Pro and same result.  When I called Acer support the person confirmed that the HDMI port is only 1080p.  I find this odd given the 1.4 spec of the input, but like I said, I have tried several machines, several cables (all rated to handle the resolutions above 1080p and 60hz) but no luck.  Hope that helps