Question about multiple GPUs

I finally broke down and purchased an Nvidia card so I could delve into GPU rendering.
So far I am quite happy. Happy enough that I want to plan a new build around multiple GPUs.

I have read that using the onboard video as your primary output allows you to share system memory with video memory to increase the scene size you can work with.

My question is does this still drop the total memory to the lowest card?
That is to say, if I put a 4GB 760 as my primary adapter would it drop to the 2GB on my 750ti then add the 500mb I have dedicated by default for my Intel chip leaving me at 2.5GB?

if so, is there a way to increase the system memory used by the Intel chip to increase the usable video memory of the 750ti?

Simple answer is no :slight_smile: You would still be limited by the 2 GB of the 750 Ti

But would running the Intel chip free up memory for the 750ti?
In other words if I load a scene onto my 750ti and run out of memory, can partially attribute that to Windows sucking up a chunk of it for the UI? If so, how would I go about finding out how much VRAM is being used by Windows?

Hi, if you use the Intel for display you have nearly all 2 GB of the GTX 750 for Cycles.
Windows use about 300 MB for the desktop, more if you have some windows open (Browser is heavy for example).

Cheers, mib

Thanks.
One last thing, would you recommend upping the amount of system ram set aside for the Intel chip in order to maximize VRAM or should I leave it at its default setting?