#Dual 1080Ti dropping frames when activating LSFG

23 messages · Page 1 of 1 (latest)

dense hemlock
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Hello. My rendering device drops 30-50% of frames when activating framegen.
Setup:

  • 2x 1080Ti stock (SLI deactivated in driver. Rendering devices forced on both NVcp and Windows 11 25H2-fresh install)
  • GPU 1 : Output card
  • GPU 2: Render card
  • 2 monitors: 3440x1440 and 1080p secondary. Tried both, conencting both screens to the output card, or just the main one, while the secondary is connected to the rendering device.
  • TR1950X on X399 board (both GPUs on PCIe3.0 X16, verified on GPU-Z)

Current settings:
Scaling OFF
Framegen:

  • LSFG 3.1 (Tried the other two without results)

  • Fixed

  • Multiplier 2

  • Flowscale 100 (tried lower without any results)

  • Sync Off

  • Mfl 3

  • HDR & Gsync ON
    GPUs as above.

Also: All kinds of overlays are turned off.

I'm monitoring my hardware with afterburner.
When not using framegen, I can see my preferred rendering card working just fine. It doesn't seem to mind outputting via the secondary card. And never did.
When I activate it though, the GPU usage and wattage curves look just as I'd imagine - about 90-100% on the rendering card and abt. 30% on the framegen card. But the framerate of the rendering card drop heavily, making the experience laggy and just overall not as I'd expect.
When trying to output via the rendering card, the result is actually better, yet smeary. But I can see on the GPU usage, that the output card is on idle then.

polar bear
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Turn off HDR, set flow rate to 60% and try again

cosmic carbon
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Both will feel pretty bad

dense hemlock
#

Thank you very much for your ideas.
I've now tried it with HDR turned off (both Windows and LSFG), aswell as lowering the flow rate, even to the lowest setting. Yet, the result stays the same.

I'm very very far off the fps cap. My overall goal is having playable framerates in demanding games. I've tried Cyberpunk2077 now.
Stock on High I'll get about 45 fps. Turning LSFG on, It'll go to 20 and below.
Similar story with other games, even when not very demanding.

On the attatched pic there's

  • Green: Rendering GPU
  • Aqua: Output GPU
  • Red: CPU
    As you can see, activating framegen gets quite a bit of load off the rendering card and starts powering the output card. Yet, on the bottom panel there's the obvious framedrop happening when LSFG kicks in, as marked.
image.png
cosmic carbon
#

hmmm, the gpu2 usage going up to 90%+ likely means that you're above the pcie bandwidth limit of your mobo, from what I've seen so far

#

Have you checked your board to make sure it's capable of at least pcie 4 x 4?

#

Some manufacturers do really, really weird nonsense with secondary and tertiary pcie lanes
--Some are throttled or disabled entirely if another is in use, or if you use an m2, or any other list of weird things

#

Otherwise the Vdroop for GPU1 is pretty intense, are you certain that your PSU can handle two 1080ti's?
That's a big ask which'd usually require a 1000W+ PSU, best to check the power cables and make sure everything is connected solidly and runs to a different PSU output

dense hemlock
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Good points. The motherboard I use is an ASUS ROG Zenith Extreme X399. Both the board and the Threadripper 1950X CPU got loads of lanes (64), which is actually the reason I built it in the first place. I've been rocking this setup since late 2017 without any issues and still many lanes to spare. (2x x16 gpu, 1x x8 networking, 3x x4 M.2, 4x Chipset). Both PCIe slots are full PCIe 3.0x16 bandwidth, as declared in the motherboards papers, the UEFI and GPU-Z as it was once built to support 4-way SLI in x16-x8-x16-x8 mode.
The power brick is a Corsair HX1200i, which does its job brilliantly, with loads of headroom.

dense hemlock
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I feel like I've found a solution, even if it's not reliably replicable: reading the post below about the 2080s and their multi-cable solution, I thought I'd plug my monitors in the other GPU while in windows and not changing settings.
Now it seems to work just as intended. No frame drops and a smooth picture.

image.png
dense hemlock
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Anyways. The solution is so simple yet not really forcable. I don't really understand what my computer tried to accomplish beforehand, but now it works - just in Furmark.
I've attached my screens to GPU 2 now, and forced GPU 1 to just render. Both CUDA and GL are forced on GPU1, aswell as Windows Graphics settings. Yet, all games now render on the opposite card. Maybe it's just a couple more hours of tinkering >.>

cosmic carbon
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LSFG would run on both my chips, added a second cable and a fake extended desktop, problem solved

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Registry edits wouldn't even populate my menu, and all my menu's still only show one of my two cards (And I've tried multiple different discrete secondary gpus)

Cannot wait for better linux support so I can get off this vibecoded slopfest

cosmic carbon
cosmic carbon
# dense hemlock Good points. The motherboard I use is an ASUS ROG Zenith Extreme X399. Both the ...

Also, your rig sounds sick, I've done a ton of xfire and various tinkering or daughter/slave setups with gpus from physX to xfire

LSFG not needing driver support and not caring about optimization nor trying to split compute tasks/loads is genuinely incredible and it's a hilarious shame this isn't how FrameGen was marketed in the first place -- since this extends GPU life dramatically and works better lmao

dense hemlock
#

Yeah Windows is really going downhill. Unreliable and overall cursed. I'm also slowly getting used to Linux on my secondary. Whenever I feel confident with it, I'll switch my main, too.
Interesting solution with the fake extended Desktop. I'll try that, too. For now, what I do, is starting a game, and then unplug the main screen to plug it into the other card. Janky af solution but it works. Cyberpunk at abt. 80 FPS is quite nice. Maybe I'll now finally take the time to actually play the game.

dense hemlock
# cosmic carbon Also, your rig sounds sick, I've done a ton of xfire and various tinkering or da...

Awesome! Sounds like you had lots of fun when building PCs was nice :D
Got the same opinion mate. This should be the way to run it.

And yeah, I'm really proud of my rig. Didn't take any cuts and went all in back then. Wanted it to last about 10 years, and it'll do more as it seems right now. Only thing I upgraded was disk capacity and some tinkering with the cooling loops.
That old ass threadripper is like a big diesel. Bit slow to start, but plenty of power and basically unstoppable.
Only thing I'm thinking of right now, is to get a GPU with a more modern output (1080Ti got DP 1.4a), so I can drive my screen at full 240Hz.
Lossless Scaling could be the perfect solution to this, since I don't really need something more powerful than a 1080Ti for most games.

cosmic carbon
dense hemlock
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Haha, janky af. Love how working with windows is like the system fooling you, and you then fooling it in return xD
Probaply will be my solution now, too, until there's a better solution to it haha

cosmic carbon
polar bear
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btw I'm assuming you have the GPUs in x16 slots 1 and 3, right?