Having two monitors plugged in - affects performance?

Duvan · 3 Sep 2011 at 17:14

I have a graphics card with a S-video port and two DVI ports.
I've got two screens plugged into the two DVI:s...
I thought that u could disable one of the monitors in the ATI program but it seems the second monitor is still showing a picture... Normally just a zoomed in version of my primary monitor's screen... but when I play games it is often identical to my primary screen.
Does this affect performance? I.e. lower FPS etc.
What if I've got the monitor set up in ATI as a extended desktop, or clone desktop... does this affect performance in games?

kedge · 3 Sep 2011 at 17:36

Duvan said:
I have a graphics card with a S-video port and two DVI ports.
I've got two screens plugged into the two DVI:s...
I thought that u could disable one of the monitors in the ATI program but it seems the second monitor is still showing a picture.

Set them to extended desktop and then you can disable one. Depending on the specs of both screens you can set them up individually. For example, i used a 4870X2 with one LCD 1680x1050 @60Hz and one CRT @ 1024x768 @85Hz.

Duvan · 3 Sep 2011 at 17:55

Thanks. Did work after trying it two times

Okay, so it does affect performance in other words?

BinnsY · 3 Sep 2011 at 18:22

I use two screens and it makes an increadibly minimal difference to performance. I think when I bothered doing 3d mark comparisons with the second screen enabled but showing nothing more than the desktop / sidebar it was about 100 points lower than with the screen completley disabled.

As long as your not running anything on the second screen it has a very very minimal effect.

Duvan · 3 Sep 2011 at 18:34

Okay. So having "clone screen" or something like that affects performance less than extended desktop (if running somethin else on the secondary screen)?

MR.B · 3 Sep 2011 at 21:05

The clone mode has absolutely no affect on performance at all, as the same image is just output to both displays, theres no extra work to do. Using extended mode has no affect in most cases, the only time where it would really make any difference is if you had multiple stuff running on each monitor of course, but just enabling a second monitor will do nothing basically.
I have two 30" 2560x1600 res screens plus a HDTV also connected to my cards and all this has no affect.

Donkeyfumbler · 5 Sep 2011 at 12:49

MR.B said:
The clone mode has absolutely no affect on performance at all, as the same image is just output to both displays, theres no extra work to do. Using extended mode has no affect in most cases, the only time where it would really make any difference is if you had multiple stuff running on each monitor of course, but just enabling a second monitor will do nothing basically.
I have two 30" 2560x1600 res screens plus a HDTV also connected to my cards and all this has no affect.

Asked the same question here a while back, and this was the agreed position there as well.