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Asus ROG PG278Q - SLI Low GPU Usage Issue

agentbb007
Level 7
After extensive testing I've determined the problem of poor SLI GPU Usage (approx 75% on GPU1 80% on GPU2) has to do with with G-SYNC SLI, it's possible it is limited to the Asus ROG PG278Q. I have 3 PG278Q's and all exhibit this same problem. If someone has another G-SYNC monitor and SLI cards please let me know if you have poor GPU usage in Witcher 3 as well.

My YouTube video below demonstrates how GPU usage fluctuates in Fullscreen and Windowed Mode on the PG278Q using SLI. I hooked up my old LG W3000h which is 2560x1600 @ 60Hz and tried Dynamic Super Resolution (DSR) and voila near 99% usage on both GPUs. Backed the resolution down to 2560x1600 and still near 99% on both cards. The minute I even hook up one of my G-SYNC PG278Q monitors even if I don't have my desktop extended to it I get the poor GPU usage issue again.

Here is a list of some things I have attempted to remedy the problem.

  • Reinstall Nvidia Drivers using Clean Install
  • Disabled G-SYNC
  • Tried different Refresh rates, currently set to 144Hz.
  • Tried hooking up only 1 PG278Q's.
  • With SLI off using only 1 Titan X GPU Usage is all good at 99%, regardless of Full Screen or Windowed.

Any ideas on how to fix this would be greatly appreciated, full system specs below.

Thanks
BB

Windows 10 Pro
3 ROG Swift PG278Q 27" 2560x1440 144Hz
Skylake i7-6700k @ 4.4Ghz with NZXT Kraken X61 Liquid Cooler
SLI GTX Titan X @ 1354Ghz
Asus Maximus VIII Hero Mobo
Samsung 850 EVO 500GB SSD
Crucial Ballistix Sport LT DDR4 2400 16GB
GeForce Driver 361.43


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6 REPLIES 6

Liquidus
Level 8
That's not a problem. It's limiting your frames to reduce tearing.

aeliusg
Level 7
He's not hovering around 144 fps, but you might be right. Has the OP tried turning off Vsync in the CP as opposed to in-game? Turning on/off windowed G-SYNC? (Also try turning off G-SYNC altogether to see if it's a driver issue or something to do with the monitor 'itself'). I no longer have SLI so I can't test it for you.

aeliusg wrote:
He's not hovering around 144 fps, but you might be right. Has the OP tried turning off Vsync in the CP as opposed to in-game? Turning on/off windowed G-SYNC? (Also try turning off G-SYNC altogether to see if it's a driver issue or something to do with the monitor 'itself'). I no longer have SLI so I can't test it for you.


Thanks for the replies guys. As you mentioned I'm not close to the 144 fps so monitor shouldn't be limiting. I've tried turning off VSync and Turning on/off all the different G-SYNC settings no luck.

As I mentioned the strange thing is I can hook up my old monitor and get 99% usage on both GPU's but if I just plug one of my Asus ROG PG278Q's into the display port my old monitor will then also exhibit the same low SLI GPU usage problem. I don't even extend my desktop to the PG278Q, just plug it in and it's like the drivers detect a G-SYNC monitor and mess up the SLI usage.

So I am quite confident that SLI combined with G-SYNC is causing the low GPU usage in Witcher 3, my old monitor can get close to 99% usage on both GPU's. Using my old monitor if I even plug a G-SYNC monitor into a display port the low GPU usage happens. This is just for Witcher 3 each game/benchmark has different GPU usage with G-SYNC and SLI.

Liquidus
Level 8
Sounds like buggy NVIDIA drivers than the monitor itself then. I was debating PG27AQ or a PB279Q, looks like I'll get the PB since GSYNC seems to be buggy and not worth the $300 price hike.

Liquidus wrote:
Sounds like buggy NVIDIA drivers than the monitor itself then. I was debating PG27AQ or a PB279Q, looks like I'll get the PB since GSYNC seems to be buggy and not worth the $300 price hike.


It's your choice, but I think it's worth it. I got my Swift on an open-box deal, and it actually turned out to be pristine. I wouldn't go back to gaming on a regular fixed-refresh display unless it was an OLED and I had enough GPU headroom to blow the top off a 120-144 hz refresh rate in every game I was playing. OP's bug is an annoyance, but you'd have a worse experience with full GPU usage at 100 fps on a regular 144 hz monitor or monitors than with less optimal GPU usage at 90 fps with G-Sync or G-Sync Surround. Depending on how long you're going to stick with your screen this time around, you could consider the extra cost to be amortized if you're going to have a qualitatively better experience over time.

Liquidus wrote:
Sounds like buggy NVIDIA drivers than the monitor itself then. I was debating PG27AQ or a PB279Q, looks like I'll get the PB since GSYNC seems to be buggy and not worth the $300 price hike.


@lIQUIDUS Even with the SLI/G-Sync GPU Uage issue in Witcher 3 I love G-SYNC and have only found this issue in Witcher 3. For example Crysis 3 runs 99% GPU Usage with SLI and G-SYNC. So I think your mileage is going to vary from game to game. And even though my old monitor has higher FPS and great GPU Usage in Witcher 3, I still prefer the way the G-SYNC monitor looks because to my eyes it provides a much smoother tear free experience.