Hi guys, I have two monitors which are LG 23EA53V and the new one I just bought is AOC i2379VH. Recently, I used this cheapo china display along with the LG23EA53V.

The old output was as follows:
DVI: LG23EA53V
HDMI: Cheap China

The new output which I wanna do is this:
DVI: LG23EA53V
HDMI: AOC i2379VH

Unfortunately, I'm having trouble with having dual 23" with my current graphics card (R9 270X). It only seems that I can have one output, either the LG23 or AOC. But I'm quite confused because when I used the china display along with the LG23, it worked fine. The china display is 23" btw

Anyone can help me?