Laptop: Dell g3
Cpu: i5 8300h
GPU: 1050 4gb
So I found it strange that I was getting a huge fps gain when playing games especially in OSU on a monitor. Over 2300average fps on monitor and when using the laptops display I would get around 400 fps. For more demanding games like ghost Recon wild lands I would get on average 7 more fps on monitor and yes I have my laptop set to use the dedicated graphics.
Some thing else I noticed is on the game OSU, when using the laptops display, the integrated graphics was also being used along with the dedicated and at times more of the integrated was used than dedicated. 60% average Integrated and 40% dedicated. And when using the monitor 0%igpu was used and 70% average was used at the average 2300fps. makes no sense to me. I read that because the laptop display is connected to the integrated igpu that dedicated graphics would have to go through the igpu and then the display rather than straight to the laptop display, like it does if you have a monitor on hdmi.
This also raises my question about latency ( if that is the correct word ) when playing games. Is it better to play games on a laptop display or monitor? For games like OSU which rely on the best response time and low input lag. I question this because on the laptop display at the average 400fps the game reaches 4.7ms average input lag and the monitor with the average 2300fps it reaches 0.50ms average. Is this to do with the frame rate or the lag from transferring video signals to multiple gpu's or am I thinking it the wrong way? Educate me you smart people why does this drop in frame rate happen on laptop displays? And why is the igpu being used so much when the dedicated gpu needs to be?
Your laptop has Nvidia Optimus for the graphics switching, which means that the iGPU is responsible for rendering the images (hence why you see load on the iGPU when not using external monitor). The display port on your laptop must be wired directly to the GPU bypassing the need for the GPU to hand off the frames to the iGPU for rendering, I guess there is some performance penalty to Nvidia Optimus (I would expect it to be a small difference though in general).
There is indeed a performance penalty for Optimus.
The FPS is limited to how fast the iGPU can draw the screen at the resolution used. This is not generally a problem at ~1920x1080 unless you are pushing extreme FPS.
You will also see a similar drop in performance as you would when recording using NVENC. I believe a similar method is used to copy the output image to the iGPU.