PyTorch 2.15 brings FP8 and faster MPS decoding to Macs
MPS in PyTorch 2.15
- Who
- PyTorch
- What
- releases PyTorch 2.15 with new MPS capabilities and performance improvements
- Quote
PyTorch 2.15 adds torch.float8_e4m3fn tensors on MPS: one byte per value, half the storage of FP16 or BF16.
What happened
Hugging Face’s PyTorch team details MPS improvements in the PyTorch 2.15 release candidate, including FP8 support and faster LLM decoding on Macs. On an M3 Ultra with torch.compile, Qwen3.6-35B-A3B decoding rises from 9.4 to 61.3 tokens/s compared with 2.14. Moving constant padding to Metal kernels also reduces peak driver memory for Wan2.2’s tiled VAE decode from about 270 GiB to 8 GiB.
Why it matters
The reported reduction in Wan2.2 video decoding memory illustrates how replacing backend operations can change the memory requirements of running an existing model on a Mac.
The story so far
PyTorch’s 2.15 release candidate adds FP8 support and faster Metal kernels to its MPS backend for Apple silicon Macs, with Hugging Face’s PyTorch team reporting faster LLM decoding and lower memory use in specific workloads. The release candidate requires macOS 15 or later and Python 3.11 or later. The new torch.float8_e4m3fn tensors on MPS use one byte per value, half the storage of FP16 or BF16. In the team’s benchmark on an M3 Ultra with torch.compile, Qwen3.6-35B-A3B decoding increased from 9.4 tokens/s with PyTorch 2.14 to 61.3 tokens/s with 2.15. The team also reported that moving constant padding to Metal kernels reduced peak driver memory for Wan2.2’s tiled VAE decode from about 270 GiB to 8 GiB.
Keep reading
Latest daily · Issue 27TorchNeuron brings native PyTorch support for Hugging Face models on AWS TrainiumTrending now
Tomorrow at 08:00, a briefing like this arrives in your inbox.
The same kind of briefing as the one above: a few stories worth reading. Free. Mail starts after you confirm, and every letter has a one-click unsubscribe. Read a past issue · 2026-10-20
