LongCat Flash Chat — Hardware Requirements & GPU Compatibility
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LongCat Flash Chat is a 561.9B-parameter open language model from meituan-longcat. It supports a context window of up to 131,072 tokens. At BF16 it needs about 1236.10 GB of VRAM — see which GPUs and Macs can run it below.
34.9K downloads
527 likesSpecifications
- Publisher
- meituan-longcat
- Parameters
- 561.9B
- Architecture
- LongcatFlashForCausalLM
- Context Length
- 131,072 tokens
- Vocabulary Size
- 131,072
- Release Date
- 2025-09-24
- License
- MIT
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HuggingFace
How Much VRAM Does LongCat Flash Chat Need?
Select a quantization to see compatible GPUs below.
| Quantization | Bits | VRAM | + Context | File Size | Quality |
|---|---|---|---|---|---|
| BF16 | 16.00 | 1236.1 GB | — | 1123.73 GB | Brain floating point 16 — preferred for training |
Which GPUs Can Run LongCat Flash Chat?
BF16 · 1236.1 GBLongCat Flash Chat (BF16) requires 1236.1 GB of VRAM to load the model weights. For comfortable inference with headroom for KV cache and system overhead, 1607+ GB is recommended. No single GPU has enough memory — multi-GPU or cluster setups are needed.
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Frequently Asked Questions
- How much VRAM does LongCat Flash Chat need?
LongCat Flash Chat requires 1236.1 GB of VRAM at BF16.
VRAM = Weights + KV Cache + Overhead
Weights = 561.9B × 16 bits ÷ 8 = 1123.7 GB
KV Cache + Overhead ≈ 112.4 GB (at 2K context + ~0.3 GB framework)
VRAM usage by quantization
BF161236.1 GB- Can NVIDIA GeForce RTX 5090 run LongCat Flash Chat?
No — LongCat Flash Chat requires at least 1236.1 GB at BF16, which exceeds the NVIDIA GeForce RTX 5090's 32 GB of VRAM.
- Can I run LongCat Flash Chat on a Mac?
LongCat Flash Chat requires at least 1236.1 GB at BF16, which exceeds the unified memory of most consumer Macs. You would need a Mac Studio or Mac Pro with a high-memory configuration.
- Can I run LongCat Flash Chat locally?
Yes — LongCat Flash Chat can run locally on consumer hardware. At BF16 quantization it needs 1236.1 GB of VRAM. Popular tools include Ollama, LM Studio, and llama.cpp.
- What's the download size of LongCat Flash Chat?
At BF16, the download is about 1123.73 GB.
- Which GPUs can run LongCat Flash Chat?
No single consumer GPU has enough VRAM to run LongCat Flash Chat at BF16 (1236.1 GB). Multi-GPU or professional hardware is required.
- Which devices can run LongCat Flash Chat?
LongCat Flash Chat requires at least 1236.1 GB at BF16, which exceeds the unified memory of most consumer devices. A high-memory Mac Studio, Mac Pro, or multi-GPU desktop setup is recommended.