RTX 5070 Ti (Blackwell) + PyTorch Nightly + Triton: Still Getting "sm_120 is not defined for option 'gpu-name'" Error

NexTGenioN: <p>Hello everyone,</p>
<p>I’m trying to get ComfyUI working on a new <strong>RTX 5070 Ti (Blackwell)</strong> GPU under <strong>Windows 11</strong>.<br>
I’ve already upgraded to the latest <strong>PyTorch Nightly</strong> with CUDA 12.8 support (which should include Blackwell support).<br>
However, I keep running into this error when running any Triton-based code (e.g., ComfyUI, Stable Diffusion):<br>
ptxas fatal   : Value ‘sm_120’ is not defined for option ‘gpu-name’<br>
RuntimeError: <code>ptxas</code> failed with error code 4294967295</p>
<p>My environment:</p>
<ul>
<li><strong>GPU:</strong> NVIDIA GeForce RTX 5070 Ti (Blackwell)</li>
<li><strong>OS:</strong> Windows 11 Enterprise x64</li>
<li><strong>Python:</strong> 3.10.6</li>
<li><strong>PyTorch:</strong> 2.8.0.dev20250528+cu128 (Nightly)</li>
<li><strong>CUDA:</strong> 12.9 Toolkit (runtime in PyTorch: 12.8)</li>
<li><strong>Triton:</strong> 3.2.0 (from pip), also tried latest main from <code>git clone</code></li>
<li><strong>ComfyUI</strong>: v0.3.34</li>
</ul>
<hr>
<p><strong>What I’ve tried:</strong></p>
<ul>
<li>Verified <strong>single PyTorch install</strong>: <code>pip show torch</code> (only one, correct version, as above)</li>
<li>Upgraded PyTorch to <strong>nightly with CUDA 12.8</strong> as per <a href="https://pytorch.org/get-started/locally/" rel="noopener nofollow ugc">PyTorch Get Started guide</a></li>
<li>Installed <strong>CUDA Toolkit 12.9</strong> (system-wide)</li>
<li>Upgraded Triton (<code>pip install --upgrade --force-reinstall triton</code>), only 3.2.0 available via pip</li>
<li>Also did <code>git clone https://github.com/triton-lang/triton.git</code> and <code>pip install .</code> in that folder (which installs 3.2.0)</li>
<li><strong>Did NOT try to build Triton from a specific tag like <code>v3.3.1</code> yet</strong> (just used the default/main branch)</li>
<li>Cleaned Python caches (<code>__pycache__</code>), cleared ComfyUI temp folders</li>
<li>Rebooted after every step</li>
<li>Drivers updated: NVIDIA 576.52 (latest as of today)</li>
<li>All software launched from the same Python environment (<code>where python</code> and <code>where pip</code> point to the same folder)</li>
<li>Environment variables (<code>CUDA_PATH</code> etc) are correct</li>
</ul>
<hr>
<p><strong>Questions / Help Needed:</strong></p>
<ol>
<li><strong>Is there an official Triton 3.3.1 pip wheel for Windows?</strong> (I only see 3.2.0)</li>
<li>Is it <strong>necessary to build Triton from source using the exact 3.3.1 tag</strong> for Blackwell support?<br>
If yes, can anyone confirm that ComfyUI / Stable Diffusion / TorchInductor work after that step, on Windows?</li>
<li>Do I need to point PyTorch or Triton to any specific binaries/libraries from CUDA 12.8/12.9?</li>
<li>Any other tweaks needed for Blackwell GPUs, e.g. editing config files, workarounds, etc.?</li>
</ol>
<hr>
<p><strong>Additional info:</strong></p>
<ul>
<li>All packages and dependencies are installed in a clean Python 3.10 environment.</li>
<li>No old PyTorch, CUDA, or Triton left over (I double-checked).</li>
<li>Still getting the <code>'sm_120' is not defined for option 'gpu-name'</code> error (see full log below).</li>
</ul>
<p><strong>Any help or pointers are very much appreciated.<br>
If someone already has Blackwell GPUs working with the PyTorch Nightly + Triton + CUDA 12.8+ toolchain on Windows, please share your working setup and exact install steps!</strong></p>
<p>Thank you!</p>

ptrblck: <p>I don’t think triton is supported on Windows, e.g. see <a href="https://github.com/triton-lang/triton/issues/1640">this issue</a>, so unsure if you are installing custom built binaries from users (and hope you have verified them). Are you seeing the same issue on Linux or WSL?</p>

NexTGenioN: <p>Hello,<br>
Thanks for the link and clarification. I understand Triton is not <em>officially</em> supported on Windows, but many users (myself included) have successfully used Triton pip wheels (up to v3.2.0) with ComfyUI/Stable Diffusion on Windows for long time. The only thing really missing is updated pip wheels for Triton 3.3.x+ with Blackwell support.</p>
<p>So, even without official support, the main request from the Windows AI community is for updated pip wheels to keep our pipelines working on new NVIDIA cards.</p>

Juan_Felipe_Zapata_E: <p>Hi everyone,</p>
<p>I’d like to add my experience to this thread, as I’m encountering a very similar issue with my RTX 50 series GPU.</p>
<p>I have a <strong>NVIDIA GeForce RTX 5070</strong>.<br>
Its compute capability is <strong>sm_120</strong> (Blackwell architecture).<br>
My operating system is <strong>Windows 10, Version 22H2 (OS Build 19045.4412)</strong>.<br>
My NVIDIA driver version is <strong>552.44</strong>.</p>
<p>I am trying to run <strong>Fooocus (v2.5.5)</strong>, and the exact error message I receive when the software attempts to utilize the GPU is:<br>
<code>RuntimeError: CUDA error: no kernel image is available for execution on the device</code></p>
<p>I’ve attempted with the following PyTorch versions within my Fooocus environment:</p>
<ul>
<li>The default version that came with Fooocus (torch-2.1.0+cu121)</li>
<li>A manual update to torch-2.5.1+cu121</li>
</ul>
<p>In both cases, the problem persists. It’s helpful to see other users with similar hardware reporting this.</p>
<p>Is there any update on the roadmap or ETA for stable PyTorch support for the sm_120 architecture? Any information regarding this compatibility would be greatly appreciated by users with RTX 50 series hardware.</p>
<p>Thank you for your time and efforts.</p>

ptrblck: <p>Blackwell is already supported in nightly and the latest stable 2.7.0 release. Select the PyTorch binary from our install matrix with CUDA 12.8 and it will work.</p>

frank85729: <p>(base) PS C:\Users\Lenovo\Desktop\Comprehensive_floder\llm-project&gt; python -c “import torch; print(‘PyTorch:’, torch.<strong>version</strong>); print(‘CUDA Available:’, torch.cuda.is_available())”<br>
Traceback (most recent call last):<br>
File “”, line 1, in<br>
File “D:\app\Lib\site-packages\torch_<em>init</em>_.py”, line 281, in<br>
<em>load_dll_libraries()<br>
File "D:\app\Lib\site-packages\torch_init</em>.py", line 264, in _load_dll_libraries<br>
raise err<br>
OSError: [WinError 1114] 动态链接库(DLL)初始化例程失败。 Error loading “D:\app\Lib\site-packages\torch\lib\c10.dll” or one of its dependencies.</p>
<p>brother help me. I have this error</p>