It's just a tech demo, but the new Shader Execution Reordering (SER) feature for DXR 1.2 looks very promising.
Microsoft is always working on DirectX behind the scenes, making large and small tweaks to the API. For its latest update, which brings the DirectX Agility SDK up to version 1.619, there are some exciting improvements to ray tracing performance.
I'm talking specifically about Shader Execution Reordering (SER), a feature that's arrived officially for DirectX Raytracing (DXR) 1.2. It had been in preview status since being announced last year at GDC 2025. The big news? Microsoft is seeing up to a 90% framerate increase with SER activated in early demos.
Let me back up for a moment. SER was originally unveiled by NVIDIA alongside its RTX 40-series graphics cards in 2022. It's a tool that reduces the performance cost of ray tracing, and not in a small way. Since its introduction, it has been used by NVIDIA and other developers, and it's a big part of Unreal Engine 5.
With Microsoft's standardized version of SER now available in DirectX, developers should have a much easier time implementingmore efficient ray tracing and path tracing across more than just NVIDIA's cards.
Why is Shader Execution Reordering (SER) in DirectX a big deal?
A look at the D3D12 Raytracing demo used by Microsoft to test SER. You can try it yourself on your hardware.
Divergence generally occurs when rays are shot unpredictably through a scene. Bouncing rays off objects in a scene makes your game look a lot more realistic, but at the same time, it can cause a GPU to lose coherence. The GPU is forced to sort these rays sequentially rather than in parallel. It's inefficient, and it puts more load on the hardware.
Adding more ray tracing cores won't fix the issue because the process takes place at the shader level. SER solves this problem by allowing the shaders to group rays into coherent batches, allowing the GPU to tackle them in parallel.
SER works alongside something called Opacity Micromaps (OMMs), another feature that allows a GPU to skip unnecessary shading when a ray bounces off an alpha-tested object. As you can guess, together this reduces the load on a GPU, which in turn improves general performance.
Just how much of a performance gain can you expect? Microsoft gives us a couple of examples from its in-house testing using a specific demo that you can also test out yourself via a GitHub repo. With SER activated on an NVIDIA RTX 4090 GPU, tests show a whopping 40% framerate increase compared to not using SER at all.
What's more impressive is that Microsoft claims it saw "a couple configurations of Intel Arc B-Series GPUs" hit a massive 90% framerate improvement with SER activated.
Windows Central's take on Shader Execution Reordering (SER)
The huge performance gains provided by Microsoft are likely not indicative of what you can expect in real-world gaming. Nevertheless, making SER a standard feature in DirectX will make it far easier for developers to implement, and that's a win for everyone.
Given how demanding path tracing can be, SER could be one of the keys to unlocking gorgeous graphics on far more GPUs that wouldn't necessarily be able to keep up without the feature. Best part? You don't need a new GPU.
I want to know what you think!
What are your thoughts on Microsoft adding SER to its latest DirectX release? Do you think real-world performance will drop significantly compared to the demos? Which GPUs do you think have the most to gain? Let me know in the comments section!
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