GPU still working w/o LCD plugged into it?

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tangoseal

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On my 8600K rig I noticed something that maybe I dont understand what is happening here?

I have an Asus ITX z370 with 8600K.

I wanted to use the IGP to test out some performance in using transcoding compared to my GPU.

Then out of curiosity I fired up a round of PubG.

I noticed that my 1070 was spooling up the fan and making heat and I was getting over 100 FPS in the game.

I had absolutely NO LCD Connection to the 1070. Only thing hooked up was display port to the mobo IO which should be the IGP.

In the BIOS I even had IGP set as primary and multi monitor was turned off.

What gives? Is the graphics card now able to render and send the rendered game graphics over the PCIe bus to the IGP display port connector?

I am really confused as to why this is working?

on the flip side when I removed the GPU, still no display connected, never was, I noticed that PUBG was horrendous perfomance. Like Very Low graphics and was only getting like 15 fps. So with GPU installed and DP connector hooked to the IGP port I get performance graphics, but removed the GPU and I get awful performance.

I know PUBG wasn't using DX12 MultiGPU tech as the game is only DX11.

Thanks and I apologize as I am not a display aficionado .
 
Master_shake_ said:
physx?
Click to expand...

Oh I doubt it was physx. There is no way I would go from 15fps on IGP to 100+ just because of physx. At least one wouldn't think. Does PUBG even use physx?

Maybe this is a new driver feature exclusive to Coffee Lake? The z370 chipset? I am searching but I don't exactly know what to search for in as far as terminology.
 
tangoseal said:
Oh I doubt it was physx. There is no way I would go from 15fps on IGP to 100+ just because of physx. At least one wouldn't think. Does PUBG even use physx?

Maybe this is a new driver feature exclusive to Coffee Lake? The z370 chipset? I am searching but I don't exactly know what to search for in as far as terminology.
Click to expand...
It may be a new compositing feature in Windows 10 and/or the NVIDIA drivers since I know a lot of first-time PC builders plug their display into their iGPU instead of their dGPU. Would be clever since I have read about an untold amount of people talking about how they are getting very poor performance compared to what they read about their hardware around the internet.
 
What kind of usage was the IGP getting when you were transcoding? Did the 1070 ramp up as well when you were transcoding?
What about normal web surfing and desktop usage? I would log/watch my GPU/IGP usage and see if they are working independently of each other or in tandem.
Almost sounds like some kind of Optimus hack is being used by NVidia or Intel. I know you said you disabled multi-monitor in the BIOS, but what about in the NVCP?
 
I use staxrip so its pretty advanced and hard to make a mistake.

As far as games .. I only tried oe gme and it ran on he 1070 with no display plugged up to it. Gonna do some more testing tonight. It has to be a new win 10 or Nvidia feature
 
What you're describing is I think how NVIDIA Optimus works on laptops. I have an older Ivy Bridge era laptop here with a discrete Quadro MXM card. When I was doing some repairs I ran the system without the GPU for a while and it just ran from the IGP, and when I put the MXM card back in it goes back to using that. But you don't have to change the connection to the LCD panel anywhere, it just pipes it through the same one used by the IGP.

I could have sworn this was a new feature starting with Skylake in Win10, worked with whatever discrete GPU you had, but everything I'm googling now is turning up stuff for virtual machine GPU passthrough and such. So I might just be hallucinating remembering (hallumbering?) that.

[edit] it was something about Lucid, they had that MVP software a few years back that allowed exactly what you're seeing. Wasn't that integrated into Intel drivers or something at one point? I can't find anything about it now.

[edit edit] ugh, maybe it was a built-in part of D3D12? Like, even if the game didn't support multi-adapter, D3D recognized your primary GPU and used that to render the game, regardless of which GPU had the physical connection to your display. Could be that this applied backwards for older titles?
 
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I tried to replicate it and cant.

I cant get it to work again.


It was so cool when it worked.
 
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