This might seem like a stupid question, but will running two displays from my computer slow down video performance?
I am aware that having a setup where it essentially makes it a 3840x1080 display WILL slow it down, but what if I am just mirroring the display? As in both monitors are showing the exact same thing. I'm no expert on how it works, but it seems to me like the graphics card doesn't have to render the display twice, but just once, and then send the signal to two monitors.
Most games do not support 2 display gaming. But mirroring is just sending the same signal to both monitors so has no impact on performance. Even just gaming on 1 and a browser on the other is negligible performance difference.
Here is my specific experience. I have an nVidia GTX 560 Ti card and was running Black Ops II at around 110 FPS. I bought a new 27" 2560X1440 monitor and set the game to native resolution. As expected my FPS dropped to 75 to 80. Then I hooked up my old monitor (1920X1200) as secondary monitor. Now when I run the game, the second monitor goes black but I only get around 20 FPS in game. As a test, I disconnected the second monitor and I was back to 75 FPS. I used to have two monitors before, but it never affected my gaming. I think the new monitor which requires dual link DVI to run at native resolution, has some adverse affect on my video card. If anyone knows why this is, please let me know.