Cloning Monitors with SLI

[drums101]

Does cloning monitors cause you to lose performance when sli is enabled? The nvidia control panel says it does but i want to know if anyone has any first hand experience with this

 

[drums101]

bump....has anyone done this and have a decrease in performance?

 

[mwarner]

I was interested in this too and couldn't find an answer. So I ran a benchmark with and without cloned display.

Setup: i7-2600K, 2 x GTX 465 1GB SLI, 24" Asus LCD + 50" Panasonic Plasma, NVidia Driver 290.53

Single Display:

Far Cry 2 @1080P Avg FPS: 153.83
Far Cry 2 @720P Avg FPS: 181.10
3dMark11 Performance mode: P6933
3dMark11 Extreme mode: X2171
GTAIV @1080P Avg FPS: 41.04
GTAIV @720P Avg FPS: 44.81

Cloned Display

Far Cry 2 @1080P Avg FPS: 112.18
Far Cry 2 @720P Avg FPS: 158.95
3dMark11 Performance mode: P6772
3dMark11 Extreme mode: X2168
GTAIV @1080P Avg FPS: 36.04
GTAIV @720P Avg FPS: 40.36


Result
The 3dMark results are essentially unaffected by clone display. GTAIV took about a 10% hit with clone mode enabled. FarCry took nearly a 30% hit at 1080P, and about 12% at 720P. So using clone mode does degrade performance. However in most cases its not going to be enough to make a visible difference. Its also worth noting the effects of clone mode are less notable at lower resolutions. I personally will continue to use clone mode unless I find a game that I need to squeeze a few more FPS out of.