Kimi K3.1 Pro vs Muse Spark Open 816B-A42B
Side-by-side VRAM requirements, benchmark scores, and GPU compatibility for local AI inference.
Quick verdict
Muse Spark Open 816B-A42B is more hardware-efficient: it needs 560.3 GB at its Q4_K_M build vs 1749.1 GB for Kimi K3.1 Pro's NVFP4, fitting on 2 GPUs natively.
Neither fits a consumer GPU? Run Kimi K3.1 Pro on 8× B300 288GB from $55.52/hr ↗
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Analysis
Muse Spark Open and Kimi K3.1 Pro were released eight days apart in October 2026, and they show two different ideas of an open frontier model. Meta's has about 820B parameters, takes text, images, video and audio, and fits on Hopper-generation servers. Moonshot's is more than three times larger and needs a Blackwell B300 node. Neither vendor has benchmarked against the other's model, so this page leans on hardware and capabilities that can be checked.
Muse Spark Open has about 42B active parameters out of about 820B (8 of 256 experts per token); Kimi K3.1 Pro has 104B active out of 2.8T. At an 8k context Muse needs 560.3 GB at this site's recommended Q4_K_M, or 598.0 GB with Meta's own 533 GB NVFP4 checkpoint, against 1,749.1 GB for Kimi's native MXFP4 checkpoint. That decides the hardware: Muse runs at Q4_K_M on eight 80 GB H100s (an estimated 38.3 tokens per second), on eight H200s, or on four B200s, while Kimi needs eight 288 GB B300s (24.2 tokens per second). Neither fits a single GPU, and a 512 GB Mac Studio holds Muse only at Q3_K_M or below. The caches behave in opposite ways. Muse puts 46 of its 62 layers on a 2,048-token sliding window, so only 16 layers grow with the context; Kimi caches 24 of 93 layers in full. Each Muse cache entry is twice as wide, though, so at the full 1,048,576-token window Muse's KV cache is 69.1 GB against Kimi's 51.5 GB, making the totals 636.7 GB against 1,806.4 GB. Million-token prompts cost Muse more in speed than in memory: on eight H100s the 1M window no longer fits in VRAM, and on four B200s the estimate drops from 49.6 to 17.0 tokens per second. On inputs, Muse is broader: text, image, video and audio against Kimi's text and image. On benchmarks, the only number both report is GPQA-Diamond: 89.0 for Muse on Meta's run against 94.2 for Kimi on Moonshot's. Meta's own table compared Muse against Kimi K3, not K3.1 Pro, and there K3's 93.5 already led. Both licenses allow commercial use and require a separate agreement for model-as-a-service businesses past $20M in annual revenue; Muse also asks for a "Built with Muse Spark Open" notice.
Bottom line: For most teams that self-host, Muse Spark Open is the practical frontier model: a third of the memory, Hopper hardware you may already own, and audio and video input Kimi lacks. Kimi K3.1 Pro is the pick when you need the strongest reasoning and agent results either vendor reports, and you have a B300 node to spare. If your workload depends on audio or video, the choice is already made.
A third of the parameters, two fifths of the active compute
Muse Spark Open's 820B total is under a third of Kimi K3.1 Pro's 2,800B, and its 42B active per token is about two fifths of Kimi's 104B.
Two ways to keep a million tokens cheap
Kimi K3.1 Pro stops most layers from caching at all. Muse Spark Open lets most layers cache but caps them at 2,048 tokens. Both reach 1,048,576 tokens; the curves show what each approach costs on the way there.
KV cache only, at FP16. Weights and activation overhead sit on top of these figures.
At the full window Muse Spark Open's KV cache is 69.1 GB against Kimi K3.1 Pro's 51.5 GB, larger despite the model being under a third of Kimi's size, because each entry on its 16 growing layers is twice as wide. The weights still decide the totals: 636.7 GB against 1,806.4 GB.
VRAM at each quantization (8k context)
| Quant | Kimi K3.1 Pro | Muse Spark Open 816B-A42B | Diff |
|---|---|---|---|
| FP32 | 12544.5 GB | 3674.6 GB | +241% |
| BF16 | 6272.4 GB | 1837.8 GB | +241% |
| FP16 | 6272.4 GB | 1837.8 GB | +241% |
| Q8_0 | 3334.0 GB | 977.3 GB | +241% |
| Q6_K | 2575.1 GB | 755.0 GB | +241% |
| Q5_K_M | 2233.3 GB | 654.9 GB | +241% |
| Q4_K_M | 1910.3 GB | 560.3 GB | +241% |
| Q3_K_M | 1508.9 GB | 442.8 GB | +241% |
| Q2_K | 1195.3 GB | 350.9 GB | +241% |
| NVFP4 | 1749.1 GB | 598.0 GB | +192% |
Diff is Kimi K3.1 Pro relative to Muse Spark Open 816B-A42B. Green = lower VRAM (fits more GPUs).
Model specifications
| Spec | Kimi K3.1 Pro | Muse Spark Open 816B-A42B |
|---|---|---|
| Org | Moonshot AI | Meta |
| Parameters | 2800B | 820B |
| Architecture | MoE (104B active) | MoE (42B active) |
| Context | 1024k tokens | 1024k tokens |
| Modalities | text, vision | text, vision, video, audio |
| License | Kimi K3.1 Pro | Muse Model License |
| Commercial | Yes | Yes |
| Released | 2026-10-23 | 2026-10-15 |
| GPUs (native) | 0 / 121 | 2 / 121 |
Benchmark scores
| Benchmark | Kimi K3.1 Pro | Muse Spark Open 816B-A42B |
|---|---|---|
| GPQA Diamond | 94.2 | 89.0 |
Green = higher score (better). N/A = not yet available. ~ = inherited from a base model, not independently reported for that release itself.
GPUs that run only Kimi K3.1 Pro(0)
Every GPU that runs Kimi K3.1 Pro also runs Muse Spark Open 816B-A42B.
GPUs that run only Muse Spark Open 816B-A42B(2)
- Apple M5 Ultra (512GB)512 GB
- Apple M3 Ultra (512GB)512 GB
Which should you use?
- • You want maximum capability and have a 1750 GB+ GPU
- • It's the newer release (2026-10-23 vs 2026-10-15); check the benchmark table above for what actually improved
- • You have limited VRAM: it's a smaller model needing 560.3 GB vs 1749.1 GB
Frequently asked questions
- Which is better, Kimi K3.1 Pro or Muse Spark Open 816B-A42B?
- Kimi K3.1 Pro has 2800B parameters vs 820B for Muse Spark Open 816B-A42B, so Kimi K3.1 Pro is the larger model. Muse Spark Open 816B-A42B is more hardware-efficient, needing 560.3 GB at its Q4_K_M build vs 1749.1 GB for Kimi K3.1 Pro's NVFP4. Muse Spark Open 816B-A42B runs on more GPUs natively (2 vs 0).
- How much VRAM does Kimi K3.1 Pro need vs Muse Spark Open 816B-A42B?
- At 8k context, Kimi K3.1 Pro needs approximately 1749.1 GB of VRAM at its NVFP4 build, while Muse Spark Open 816B-A42B needs 560.3 GB at its Q4_K_M build. At the largest build each ships, Kimi K3.1 Pro requires 6272.4 GB (FP16) vs 1837.8 GB (FP16) for Muse Spark Open 816B-A42B.
- Can you run Kimi K3.1 Pro on the same GPUs as Muse Spark Open 816B-A42B?
- These models have very different VRAM requirements, so they do not share the same compatible GPU set.
- What is the difference between Kimi K3.1 Pro and Muse Spark Open 816B-A42B?
- Kimi K3.1 Pro has 2800B parameters (104B active, MoE) with a 1024k context window. Muse Spark Open 816B-A42B has 820B parameters (42B active, MoE) with a 1024k context window. Licensing differs: Kimi K3.1 Pro is Kimi K3.1 Pro while Muse Spark Open 816B-A42B is Muse Model License.
- Which model fits in 24 GB of VRAM, Kimi K3.1 Pro or Muse Spark Open 816B-A42B?
- Neither fits in 24 GB: Kimi K3.1 Pro needs 1749.1 GB at NVFP4 and Muse Spark Open 816B-A42B needs 560.3 GB at Q4_K_M. Both require a multi-GPU server with 1750 GB+ of combined VRAM.
- Which handles long context better, Kimi K3.1 Pro or Muse Spark Open 816B-A42B?
- At the full window Muse Spark Open's KV cache is 69.1 GB against Kimi K3.1 Pro's 51.5 GB, larger despite the model being under a third of Kimi's size, because each entry on its 16 growing layers is twice as wide. The weights still decide the totals: 636.7 GB against 1,806.4 GB.