Low fps with GTX 970 on XB270HU

[gavagai]

I just picked up an Acer XB270HU. It looks incredible, but running a second monitor (a 24" 1080p tv) kills the frame rate (think <10 fps) whenever a game is running on the acer. Do I need to upgrade to a GTX 980 ti to run dual monitors? Thanks.

CPU: i5 760 (2.8GHz)
GPU: ASUS GeForce GTX 970
RAM: G.SKILL Ripjaws Series 8GB (2 x 4GB) DDR3
Mobo: ASUS P7P55D-E Pro LGA 1156 Intel P55 SATA 6Gb/s
PSU: SILVERSTONE ST75F-P 750W ATX 12V
Monitor 1: XB270HU
Monitor 2: 1080p HDTV
Windows 10

 

[ashesofempires04]

It's likely because you're running two different resolutions. Have you tried setting the resolution of your 1440p monitor to 1080 and noted the framerate?

 

[gavagai]

That led me down the right path -- having the game set to fullscreen rather than borderless windowed (fake fullscreen) mode seemed to be causing the problem. In borderless windowed mode, I'm getting 60-80fps even with two different resolutions.