Disabling iGPU

Sorry if this is a noob question, but how much performance do you gain by disabling the iGPU? I've heard that it will free up RAM which sorta makes sense but I've also heard that it will decrease CPU load. How is that possible if they dGPU is running? Does the render somehow get split? Also, if I run the dGPU all the time, how much extra power consumption would I be seeing?

 

First of all, freeing up RAM only makes a difference if what's left is not or just barely enaugh.
If you have 16GB of RAM and while doing lots of things about 10GB are still available/free, freeing up another 100MB won't make any difference.

Second thing is that decreasing CPU load is good, as it means the CPU has to do less things, but that should not be affected by the iGPU (though it's part of the CPU and therefore might use some of its cache).

The rendering is either done exclusively by the iGPU or the dedicated one, nothing gets split.

If you were to run the dGPU all the time and not let it sleep (enduro/optimus) then your battery life will decrease, probably by a lot and you won't see any real performance gains as your notebook should generally choose the right GPU for every task (gaming = dGPU, office = iGPU).

BUT: Depending on which model you have, it might not be possible to disable the iGPU as the signal from the dGPU gets routed thru it and there is no direct connection between any screen and the dGPU. <- very likely if you have an iGPU

 

Ok so it shouldn't make any difference. With that in mind, how come people tell you to disable the iGPU when giving benchmark scores? 2 threads for example.
https://www.techpowerup.com/forums/threads/unigine-heaven-4-0-benchmark-scores.198888/
http://www.overclock.net/t/1235557/official-top-30-heaven-benchmark-4-0-scores

 

In both threads this is meant for desktop systems, not notebooks.

The reason is that a desktop PC typically has a direct connection between the dedicated graphics card and the monitor / display, therefore disabling the integrated one is possible and the higher powerdraw doesn't matter.

DON'T compare full desktop PCs to notebooks, they are MUCH more flexible.

If you have a notebook with an iGPU it is VERY likely you can't disable it because the dGPU gets routed through it, as i already mentioned above.

 

MUX switch (the ONLY way you can have Gsync AND the ability to use the iGPU).

 

2 reasons:

Because Intel/Nvidia's switching software (optimus as it was once called) slows down benchmarking scores. Not enough to make a real world difference, but any difference is enough for competitive benchmarking.

Also iGPU graphics switching gives noticeable hiccups in day to day tasks that some find annoying (i.e. on some systems systems clicking on system tray cases a short freeze, or some older/indie games have to manually list the game in Nvidia control panel to get the dGPU to run it)

 

Yep, plus competitive BM is nonsense with a notebook (probably triggering some people here^^).

I have yet to see noticeable hiccups on any nvidia/intel or amd/intel notebook but the indie/old games thing can certainly be annoying.

Still with many notebooks it simply is not possible to run just the dGPU and disable the i one.

Keep in mind that these switching notebooks have a great advantage when it comes to mobility and battery life compared to those with just a dGPU.

 

Competitive benchmarking is nonsense... full stop.

 

It's a sport really, but you start getting in to what does compute mean for most people and it all gets kind of philosophical.