Onboard with Offboard Graphics Combined Performance

[ben_xman]

So, say I (will eventually) have this build:

- Windows 10
- i3 8100
- MSI Z370 SLI PLUS
- RX480

and three monitors:
- MSI Optix G27C
- HP Compaq LA2405x
- Dell 1907FP
(Weird assortment, I know.)

If I hook up the Dell to onboard graphics and the other two monitors to the card, would that lead to better performance? Maybe juggle the monitors to ports?

 

[2Be_or_Not2Be]

Short answer - no, it's not really going to improve performance. The main reason is that the application is sending its "draw" requests to the GPU assigned to it. As such, the graphics driver is only sending the rendering requests to the GPU it's "driving".

If you were wanting a SLI/Crossfire-type of application support (wherein two or more GPUs are driving graphics for a single app), then usually this is accomplished through support for GPUs from the same family made by the same vendor (i.e. multiple GPUs made by AMD, multiple GPUs made by Nvidia, etc.). Their graphics driver handles sending the requests to the multiple GPUs. In this case, you have the onboard graphics from Intel and a RX480 from AMD. That type of cross-vendor multi-GPU usually doesn't work together to speed up one app as they have different drivers for the different GPUs, not one unified driver. There is development work going on in DirectX to support vendor-agnostic multi-GPU setups (like a Nvidia GPU & AMD GPU together), but it's not quite there like SLI/Crossfire is today.

But take heart, SLI/Crossfire multi-GPUs usually don't give a direct multiple-based boost to performance (i.e. you can't multiply frame rates times # of GPUs installed; it's not 1 GPU gets me 60fps, so 2x GPU will give me 120fps). It's more of a progressive bump up, as long as the app & driver support it (so 2x GPU would give you more like 90fps). Sometimes SLI/Crossfire setups even have their own unique problems with apps.

In regards to connecting your monitors, there are benefits to having one GPU driving all of the monitors. You can then have multi-monitor setups (like AMD's Eyefinity) that are sometimes supported in games (like racing simulations or flight simulators) for multi-angle views. Of course, it also makes it easy for multi-monitor setups in Windows to do things like expanding your desktop, etc.