Noob Q: Duplicate display = duplicate render?

[cbrunny]

If you have a display that is being duplicated, is the image being rendered twice, or just displayed twice?

Put another way, if I duplicate a display and play Bioshock Infinite, which I normally get 60 fps pretty solid, will the performance suffer more than 1 or 2 percent?

 

[nightspydk]

That's a funny question.
No matter what you put on the screen, your gpu will have to render it. The only difference might be with the ram. Some information might be stored there, just like when you are browsing. Also the vram.

In short yes your performance will suffer unless you code a special program for that.

That's how I see it.

 

[cbrunny]

Hmm.. Interesting. Surprisingly, not the answer I was expecting. I would have figured it was one render displayed twice... so my gpu would be working twice as hard?

 

[bystander36]

I don't know for sure, but I'd assume the memory buffer dedicated to being displayed to the monitor would be shared by both monitors. That would mean you'd only have to render it once, and the refresh cycle of the monitors would have them both read and update their images from the same buffer.

 

[parvadomus]

It is rendered only 1 time, into a buffer in video memory. Its displayed on both displays, your penalty is close to 0 fps.

 

[cbrunny]

Beauty!