# Some sort of "tearing" visible when running ParticleEffects Demo with Vulkan **URL:** \ **Category:** Rendering\ **Tags:** vulkan, reproducible-bug, unreal-engine, Rendering, question\ **Created:** [November 20, 2018, 3:40pm UTC](https://forums.unrealengine.com/t/some-sort-of-tearing-visible-when-running-particleeffects-demo-with-vulkan/437984 "2018-11-20T15:40:18Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![John\_Alcatraz](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@John\_Alcatraz](https://forums.unrealengine.com/u/John_Alcatraz)\ **Post date:** [November 20, 2018, 3:40pm UTC](https://forums.unrealengine.com/t/some-sort-of-tearing-visible-when-running-particleeffects-demo-with-vulkan/437984/1 "2018-11-20T15:40:18Z")
I’ve looked at the particle effects demo with Vulkan in 4.21, and I have not done any performance testing, I only packaged the demo in Shipping config with D3D11 and Vulkan APIs enabled, and then compared how it feels to run the resulting exe regularly, and with -vulkan. I feel no performance difference, likely because both are running into the default VSync, GPU usage is at ~55% with both D3D11 and Vulkan. Both feel nice and responsive. There is only 1 difference: With Vulkan, there is visible “tearing”. Very easy to reproduce. Position the camera here: ![259950-chrome-2018-11-20-16-37-32.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/4/6/a/46ab50e5d52c8a2e964f2c573e2a73c6ea7f6385.png) And then use the A and D button to move the camera left/right. There are “lines wandering through the image up/down”. Is this a known issue @RCaloca ? Using Win10, GTX 1080, 416.X driver. ---
**Author:** ![RCaloca](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@RCaloca](https://forums.unrealengine.com/u/RCaloca)\ **Post date:** [November 20, 2018, 4:01pm UTC](https://forums.unrealengine.com/t/some-sort-of-tearing-visible-when-running-particleeffects-demo-with-vulkan/437984/2 "2018-11-20T16:01:18Z")
Hey John, any way you can make a small video showing? I haven’t been able to repro here. Are you running fullscreen or windowed? ---
**Author:** ![John\_Alcatraz](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@John\_Alcatraz](https://forums.unrealengine.com/u/John_Alcatraz)\ **Post date:** [November 20, 2018, 4:14pm UTC](https://forums.unrealengine.com/t/some-sort-of-tearing-visible-when-running-particleeffects-demo-with-vulkan/437984/3 "2018-11-20T16:14:04Z")
It’s switching to fullscreen by default, so that’s how I run it. I just tried to record it using Shadowplay, but the issue is not visible on that recording. So I guess I’ll have to try to capture it with my phone 🙂 ---
**Author:** ![John\_Alcatraz](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@John\_Alcatraz](https://forums.unrealengine.com/u/John_Alcatraz)\ **Post date:** [November 20, 2018, 4:34pm UTC](https://forums.unrealengine.com/t/some-sort-of-tearing-visible-when-running-particleeffects-demo-with-vulkan/437984/4 "2018-11-20T16:34:45Z")
@RCaloca Here, I’ve recorded a video with my phone that does show the issue: > **[VulkanTearingIssue.mp4](https://drive.google.com/file/d/1Q4NH9HQWrBjasoTbYwqYRCxiWDzCI8va/view?usp=sharing)** > > Google Drive file. I have recorded in 120 fps and slowed it down to 33% speed. Quality isn’t great, but you clearly see the tearing. I know filming a 60 hz panel with a 120 fps camera in general isn’t ideal - but I can definitely not see anything like this when running it with D3D11 instead of Vulkan, that’s perfectly smooth. So it’s some issue with the rendering by Vulkan. ---
**Author:** ![RCaloca](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@RCaloca](https://forums.unrealengine.com/u/RCaloca)\ **Post date:** [November 20, 2018, 8:12pm UTC](https://forums.unrealengine.com/t/some-sort-of-tearing-visible-when-running-particleeffects-demo-with-vulkan/437984/5 "2018-11-20T20:12:51Z")
Got it; that’s tearing due to vsync. If you do r.vsync 2 it goes away. We’ll investigate, thanks! ---
**Author:** ![RCaloca](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@RCaloca](https://forums.unrealengine.com/u/RCaloca)\ **Post date:** [November 20, 2018, 8:14pm UTC](https://forums.unrealengine.com/t/some-sort-of-tearing-visible-when-running-particleeffects-demo-with-vulkan/437984/6 "2018-11-20T20:14:54Z")
Entered internal issue UE-66777 to look into. ---
**Author:** ![John\_Alcatraz](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@John\_Alcatraz](https://forums.unrealengine.com/u/John_Alcatraz)\ **Post date:** [November 20, 2018, 8:32pm UTC](https://forums.unrealengine.com/t/some-sort-of-tearing-visible-when-running-particleeffects-demo-with-vulkan/437984/7 "2018-11-20T20:32:11Z")
Great! Happy to hear it wasn’t a known issue yet, so that it was actually useful for me to report 🙂