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2.81 much worse look dev performance than 2.80
Closed, InvalidPublic

Description

System Information
Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce MX130/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.12

Blender Version
Broken: version: 2.81 (sub 16), branch: master, commit date: 2019-11-20 14:27, hash: rB26bd5ebd42e3
Worked: (optional)

Short description of error
[Please fill out a short description of the error here]
Blender 2.81 has very bad look dev performance in comparison to 2.80
In this GIF: 2.80 on the left, 2.81 on the right:
GIF, that shows the bad performance

Exact steps for others to reproduce the error
[Please describe the exact steps needed to reproduce the issue]
go into look dev or "material preview"
[Based on the default startup or an attached .blend file (as simple as possible)]

Event Timeline

Experiencing the same thing in my case. Came here to look for any reports of it.

My system configuration:

System Information
Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce GTX 970/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.20

First thing I did so far was updating my nVidia drivers since I was using quite old ones, but after doing it and PC restart no change so far.

This comment was removed by Tomek (VGT).

I'm trying to reproduce it with creating scene from scratch and seems it's not happening. It might be that we have something specific used in our blend files that triggers this issue.

I'm able to provide my file where I am reproducing it. You can try to open it in 2.80 and 2.81. From what I am seeing so far, mesh with red material assigned to it is slowing 2.81 mostly. When this object is hidden or material from it removed it's much more responsive.

Another update for my file. When you inspect material for that mesh, there is a group node called "rust mask". Removing it speeds up lookdev a lot. Something inside of it is big slowdown.

Can you guys check if eevee settings all both the same? in both versions?

You mean in the opened projects? For me it's the exact same save, no changes done. When I open it in 2.80 it's fine, in 2.81, it's not.

2.81 brings a bit of new settings and options for eevee... so even tho the file have same stuff.. some stuff that was not avable in 2.8 is turned on in 2.81 might check this.

Tomek (VGT) added a comment.EditedNov 21 2019, 10:59 PM

I tried to simplify as much as I could and now I have a clean new starting blend file with a cube where I only appended simplified material I used. When I try to rotate view around cube in shading workspace, it's really lagging (seems to be important that cube is taking a lot of visible area. If I zoom out, performance increases). If I will disconnect bump node on any of those two bsdf shaders, or disconnect noise node on mix shader it's gaining a lot of fps all of a sudden. Looks like some combination of bump noise and shader mixing is triggering this for me.

A qualified developer needs to be able to reproduce the problem to fix.
But this one is very specific as it depends on the OS and GPU.

You can try to update the drivers, sometimes it solves. See https://docs.blender.org/manual/en/dev/troubleshooting/gpu/index.html

@Clément Foucault (fclem), any idea what might have introduced this regression?

Clément Foucault (fclem) changed the task status from Unknown Status to Invalid.Nov 22 2019, 11:25 PM
Clément Foucault (fclem) claimed this task.

The bump node is much higher quality in 2.81. But it basically triple the cost of the bump node height shader branch. Since you are using noise which is one of (if not "the") most expensive nodes it just get to a point where perf takes a big hit.

So I wouldn't consider this a bug.

From the release notes:

Bump mapping was changed to give more accurate results closer to Cycles. In particular it makes bump mapping with procedural textures work much better than before, at the cost of some performance.