GLM-4 32B-0414 on L20 48GB (48GB) — VRAM, KV Cache & Throughput

GLM-4 32B-0414 (32B total, 32B active, Dense GQA) uses 18.44 GiB of 4-bit weights (Q4_K_M), requiring 20.92 GiB total at 8K context and 26.64 GiB at 32K on L20 48GB (~27.7 tok/s decode).

Interactive Sizing Workbench

Full Compatibility Report →
48 GB · 864 GB/s
Fits with Safe Headroom
Config-derived formula HF config.json ↗
Memory Allocation Breakdown (GiB) 20.92 GiB (22.46 GB) / 48 GiB (44%)
Model Weights: 18.44 GiB KV Cache & State: 1.91 GiB Runtime & Activation Buffers: 0.57 GiB System RAM Offload: 0 GiB
Required GPU Memory
20.92 GiB
22.46 GB (decimal)
Usable Hardware Memory
45.6 GiB
48 GB (physical)
Safe Headroom
+24.68 GiB
44% utilization
Est. Decode Throughput
~27.7 tok/s
32B active params
Est. Prefill Throughput
~975 tok/s
4K Prompt TTFT: ~4201 ms
Est. Cost / 1M Tokens
$1.90
Dense GQA · MIT

Recommended Hardware for Current Configuration

Best Single GPU
Arc Pro B60 24GB (24GB)
~$599
Best Value / Used GPU
RTX 3090 (24GB)
~$750
Apple Unified Memory
Ryzen AI Max+ 395 128GB
~$1,999
Cloud From
Vast.ai · $0.19 / hr
1x RTX 3090

Production Launch Commands

llama.cpp (GGUF)
llama-server -hf unsloth/GLM-4-32B-0414-GGUF:Q4_K_M \
  --ctx-size 8192 -ngl 999 --flash-attn
vLLM
vllm serve THUDM/GLM-4-32B-0414 \
  --max-model-len 8192 --gpu-memory-utilization 0.92
Live Token Speed Simulator (TTFT ~4201ms · ~27.7 tok/s)
[GLM-4 32B-0414 · 20.92 GiB] allocated on target GPU. Prefill completed in TTFT window; streaming autoregressive tokens at memory-bandwidth-bound rate...

Cloud GPU Comparison & Rent-vs-Buy TCO

Verified public rates across RunPod, Vast.ai, Vultr, and DigitalOcean.

Verified: 2026-11-04
Purchase break-even
~26.6 months
Est. local power: $4.26 / mo
Provider Recommended Instance Total VRAM Hourly Rate Monthly at Selected Hours Billing Mode Deploy
RunPod 1x RTX 3090 (Community Cloud) 24 GB $0.22 / hr $26.75 / mo Per-second Deploy GPU ↗
Vast.ai 1x RTX 3090 (Verified Host) 24 GB $0.19 / hr $22.98 / mo Spot / On-demand Deploy GPU ↗
Vultr ($300 Free Credit*) 1x L40S 48GB (Dedicated Instance · $300 Credit*) 48 GB $1.67 / hr $203.19 / mo Hourly Deploy GPU ↗
Vultr Cloud GPU 1x L40S 48GB (Dedicated Instance) 48 GB $1.67 / hr $203.19 / mo Hourly Deploy GPU ↗
DigitalOcean 1x RTX 6000 Ada (Dedicated Instance) 48 GB $1.57 / hr $190.91 / mo Per-second Deploy GPU ↗

Rates reflect public listings on the verification date and fluctuate with regional inventory.

Fine-Tuning VRAM Requirements (QLoRA / LoRA / Full) — GLM-4 32B-0414

QLoRA (4b) Fits with Safe Headroom
24.06 GiB
Model Weights: 18.44 GiB · Gradients + Optimizer: 4.48 GiB · Act: 1.14 GiB
Recommended GPU: Radeon AI PRO R9700 32GB (32GB)
LoRA (16b) Exceeds Available GPU Memory
68.16 GiB
Model Weights: 59.6 GiB · Gradients + Optimizer: 7.04 GiB · Act: 1.52 GiB
Recommended GPU: RTX PRO 6000 Blackwell (96GB)
Full BF16 Exceeds Available GPU Memory
247.05 GiB
Model Weights: 59.6 GiB · Gradients + Optimizer: 184.76 GiB · Act: 2.69 GiB
Recommended GPU: Instinct MI355X 288GB (288GB)

Engineering Sizing Notes & Optimization Playbook

Quick Hardware Verdict

L20 48GB (48GB physical, 45.6 GiB usable) runs 4-bit (Q4_K_M) GLM-4 32B-0414 at 8K context using 20.92 GiB with 24.68 GiB of safe headroom (~27.7 tok/s single-stream decode).

KV Cache & Runtime Tuning

GLM-4 32B-0414 uses Dense GQA (32B total, 32B active per token). Moving from 8K to 32K context expands FP16 KV cache from 1.91 GiB to 7.63 GiB; enabling 8-bit KV cache (llama.cpp -ctk q8_0 -ctv q8_0 or vLLM --kv-cache-dtype fp8) saves 3.82 GiB at 32K (reducing total VRAM to 22.82 GiB).

VRAM Scaling Across Context Windows (4K to 128K, 4-bit Weights)

GLM-4 32B-0414 VRAM scaling from 4K to 128K context (4K: 19.95 GiB, 8K: 20.92 GiB, 32K: 26.64 GiB, 128K: 49.51 GiB) 4K 19.95 GiB (KV 0.95 GiB) 8K 20.92 GiB (KV 1.91 GiB) 32K 26.64 GiB (KV 7.63 GiB) 128K 49.51 GiB (KV 30.5 GiB) L20 48GB (48GB)
Model weights remain constant while attention KV cache grows with context length and batch size.

Quantization Precision & Memory Matrix — GLM-4 32B-0414 @ 8K

Quantization Format Weights (GiB) KV Cache Total VRAM (GiB) Decode Speed Compatibility (L20 48GB) Recommended GPU Data Source
Native Weights (BF16 / FP8 / MXFP4 — Lossless) (BF16) 59.6 GiB 1.91 GiB 62.08 GiB (66.66 GB) ~2.8 tok/s Exceeds Available GPU Memory RTX PRO 6000 Blackwell (96GB) Official checkpoint size
FP8 / GGUF Q8_0 (8-bit — Near-Lossless) (Q8_0) 31.66 GiB 1.91 GiB 34.14 GiB (36.66 GB) ~16.4 tok/s Fits with Safe Headroom A40 48GB (48GB) Config-derived formula
GGUF Q6_K (6-bit — High Precision) (Q6_K) 24.44 GiB 1.91 GiB 26.92 GiB (28.91 GB) ~21.1 tok/s Fits with Safe Headroom Radeon AI PRO R9700 32GB (32GB) Config-derived formula
GGUF Q5_K_M (5-bit — Balanced) (Q5_K_M) 21.39 GiB 1.91 GiB 23.87 GiB (25.63 GB) ~24 tok/s Fits with Safe Headroom Radeon AI PRO R9700 32GB (32GB) Config-derived formula
Q4_K_M / UD-Q4_K_XL / AWQ (4-bit — Recommended) (Q4_K_M) 18.44 GiB 1.91 GiB 20.92 GiB (22.46 GB) ~27.7 tok/s Fits with Safe Headroom Arc Pro B60 24GB (24GB) Config-derived formula
GGUF IQ4_XS (4.25-bit — Compact) (IQ4_XS) 16.1 GiB 1.91 GiB 18.58 GiB (19.95 GB) ~31.5 tok/s Fits with Safe Headroom Arc Pro B60 24GB (24GB) Config-derived formula
GGUF Q3_K_M (3-bit — Low VRAM) (Q3_K_M) 14.8 GiB 1.91 GiB 17.28 GiB (18.55 GB) ~34.1 tok/s Fits with Safe Headroom Arc Pro B60 24GB (24GB) Config-derived formula
GGUF UD-Q2_K_XL (2-bit — Extreme MoE) (UD-Q2_K_XL) 10.62 GiB 1.91 GiB 13.1 GiB (14.07 GB) ~46.5 tok/s Fits with Safe Headroom RTX 4060 Ti 16GB (16GB) Config-derived formula

Technical Specifications & FAQ

Does GLM-4 32B-0414 fit on L20 48GB (48GB)?

In 4-bit (Q4_K_M) at 8,192 context, GLM-4 32B-0414 requires 20.92 GiB total GPU memory (18.44 GiB weights + 1.91 GiB KV cache + 0.57 GiB runtime buffers) against 45.6 GiB usable on L20 48GB, delivering ~27.7 tok/s decode.

How much VRAM does GLM-4 32B-0414 need at 32K context?

At 32,768 context tokens, GLM-4 32B-0414 (Dense GQA) allocates 7.63 GiB for KV cache and state, bringing total 4-bit VRAM to 26.64 GiB (28.6 GB decimal).

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