How much GPU memory does GLM-4.7-Flash need?
GLM-4.7-Flash by Z.ai has 31.2B parameters, 3B of them active for each token. Its weights take 62.4 GB at 16-bit, 31.2 GB at 8-bit and 17.6 GB at 4-bit; released in BF16, its files are 62.4 GB. Each token of a conversation adds 54.1 KB of KV cache, so a 32K conversation holds 1.77 GB.
Z.ai · released in BF16
GLM-4.7-Flash at a glance
- Parameters
- 31.2B
- 3B active for each token
- As released
- 62.4 GB
- Its BF16 files
- At 16-bit
- 62.4 GB
- At 4-bit
- 17.6 GB
- NVFP4
- KV cache a token
- 54.1 KB
- At 16-bit
- Longest context
- 202,752
- Tokens
GPUs needed at each number format
For 1 conversation of 32,768 tokens with a 16-bit KV cache, counting 92% of each GPU's memory as vLLM does. Under each count, the most tokens a second memory allows.
| GPU | Memory | 16-bit | 8-bit | 4-bit |
|---|---|---|---|---|
| L4 | 24 GB | 4 GPUs154 tokens/s | 2 GPUs126 tokens/s | 1 GPU87 tokens/s |
| GeForce RTX 5090 | 32 GB | 4 GPUs922 tokens/s | 2 GPUs751 tokens/s | 1 GPU518 tokens/s |
| L40S | 48 GB | 2 GPUs222 tokens/s | 1 GPU181 tokens/s | 1 GPU250 tokens/s |
| A100 80GB | 80 GB | 1 GPU262 tokens/s | 1 GPU427 tokens/s | 1 GPU589 tokens/s |
| H100 | 80 GB | 1 GPU431 tokens/s | 1 GPU702 tokens/s | 1 GPU968 tokens/s |
| RTX PRO 6000 Blackwell | 96 GB | 1 GPU231 tokens/s | 1 GPU375 tokens/s | 1 GPU518 tokens/s |
| DGX Spark | 128 GB | 1 GPU35 tokens/s | 1 GPU57 tokens/s | 1 GPU79 tokens/s |
| H200 | 141 GB | 1 GPU617 tokens/s | 1 GPU1,005 tokens/s | 1 GPU1,387 tokens/s |
| B200 | 180 GB | 1 GPU1,029 tokens/s | 1 GPU1,676 tokens/s | 1 GPU2,311 tokens/s |
| Instinct MI300X | 192 GB | 1 GPU682 tokens/s | 1 GPU1,110 tokens/s | 1 GPU1,531 tokens/s |
| Instinct MI325X | 256 GB | 1 GPU772 tokens/s | 1 GPU1,257 tokens/s | 1 GPU1,733 tokens/s |
| Instinct MI355X | 288 GB | 1 GPU1,029 tokens/s | 1 GPU1,676 tokens/s | 1 GPU2,311 tokens/s |
Models of a similar size
- Gemma 4 26B A4B25.8B parameters, 14.5 GB at 4-bit
- Qwen3.8 27B27.8B parameters, 15.6 GB at 4-bit
- Granite 4.2 30B29.3B parameters, 16.5 GB at 4-bit
- Gemma 4 31B31.3B parameters, 17.6 GB at 4-bit
- Nemotron 3.5 Lightning 30B A3B31.6B parameters, 17.8 GB at 4-bit
- Qwen3.6 35B A3B36B parameters, 20.2 GB at 4-bit
Questions
- How much VRAM does GLM-4.7-Flash need?
- 62.4 GB for its weights at 16-bit, 31.2 GB at 8-bit and 17.6 GB at 4-bit, plus the KV cache: 54.1 KB for each token, 1.77 GB for a conversation of 32K tokens and 11 GB at its longest context of 202,752 tokens. The server also keeps about 8% of each GPU free.
- Can GLM-4.7-Flash run on 1 GPU?
- Yes, at 4-bit: the smallest single GPU here that holds it with a 32K conversation is the L4.
- How many H100s does GLM-4.7-Flash need?
- With 1 conversation of 32K tokens, 1 H100 at 16-bit and 1 H100 at 4-bit. Each H100 has 80 GB, of which vLLM uses 92% by default.
- Can I run GLM-4.7-Flash on an RTX 5090?
- The RTX 5090 has 32 GB. With a 32K conversation, GLM-4.7-Flash needs 1 GeForce RTX 5090 at 4-bit and 4 GeForce RTX 5090s at 16-bit.
- How fast does GLM-4.7-Flash run?
- At 4-bit on 1 H100, memory lets 1 conversation get at most 968 tokens a second. Real servers reach part of that ceiling, and each conversation gets less when many run at once.
Sources
Where each fact comes from
- 1Hugging Face: zai-org/GLM-4.7-Flash
- 2vLLM: Engine arguments (gpu_memory_utilization)
- 3vLLM: Hybrid KV cache manager
- 4vLLM: Parallelism and scaling
- 5NVIDIA: Introducing NVFP4
- 6NVIDIA: L4 specifications
- 7NVIDIA: GeForce RTX 5090 specifications
- 8NVIDIA: L40S specifications
- 9NVIDIA: A100 80GB specifications
- 10NVIDIA: H100 specifications
- 11NVIDIA: RTX PRO 6000 Blackwell specifications
- 12NVIDIA: DGX Spark specifications
- 13NVIDIA: H200 specifications
- 14NVIDIA: B200 specifications
- 15AMD: Instinct MI300X specifications
- 16AMD: Instinct MI325X specifications
- 17AMD: Instinct MI355X specifications