llmrun
Z.aiGLM 5Glm5NextForConditionalGeneration

GLM 5.3 Flash — Hardware Requirements & GPU Compatibility

VisionFunctions

GLM 5.3 Flash is a vision-language model from Z.ai in the GLM 5 family, with roughly 321 billion parameters. The Flash designation points to a variant tuned for faster inference within the family, and the model accepts image input alongside text, making it usable for tasks that combine visual and textual understanding. It supports a 1M token context window, useful for long documents or multi-image conversations, and ships under the MIT license. At its parameter scale, local deployment needs multi-GPU or server-class hardware; most users will reach it through a hosted endpoint rather than running it on a single machine.

321.3B params · MoE18B active1049K contextMIT6.5M downloads2.9K likes1.0M quant downloads

GLM 5.3 Flash runs on a 256 GB+ Mac or a datacenter GPU

Best local pick → Mac Studio (M3 Ultra, 256GB) · Q4_K_M · 205.2 GB · ~35 tok/s

Macs from128 GB IQ2_S · ~52 tok/s

Score 124.2#9 of 100 open#4 of 84 that fit ≤256 GBMIT

Not set up for it?

Reference GPU · RTX 4090 24 GB

Estimates, ±20% · how we estimate

Run GLM 5.3 Flash

One recommended way. Every other method, OS and quant is in the step-by-step guide.

Recommended

Ollama
one command · needs Ollama installed
$ollama run hf.co/batiai/GLM-5.3-Flash-GGUF:Q4_K_M

Q4_K_M runs on one Instinct MI325X 256 GB · 16K context

Download: GLM-5.3-Flash-Q4_K_M-00001-of-00004.gguf188.67 GB + 3 partsbatiai

install, OS, other quants

Other ways

each opens step-by-step

Run in cloud

Fits on B300 (288 GB) (82 GB headroom) · Q4_K_M

Generation speed
~217 tok/s
generation speed
Cost per 1M output tokens
$8.89
per 1M output tokens

How Much VRAM Does GLM 5.3 Flash Need?

Select a quantization level; the listed hardware adheres to it.

QuantizationVRAM+32KRuns on
90.2 GB112.8 GB2-bit · i-quant extreme compression — Importance-weighted 2-bit, extreme compression — significant quality lossRuns on Instinct MI250X 128 GB
102.2 GB124.9 GB2-bit · i-quant small — Importance-weighted 2-bit, smallRuns on Instinct MI250X 128 GB
138.4 GB161 GB2-bit · K-quant — 2-bit quantization with K-quant improvementsRuns on B200 192 GB
158.4 GB181.1 GB3-bit medium — 3-bit medium quantizationRuns on B200 192 GB
194.6 GB217.3 GB4-bit medium — 4-bit medium quantization — most popular sweet spotRuns on Instinct MI325X 256 GB
230.8 GB253.4 GB5-bit medium — 5-bit medium quantization — good quality/size tradeoffRuns on Instinct MI325X 256 GB
266.9 GB289.6 GB6-bit, very good — 6-bit quantization, very good qualityRuns on Instinct MI350X 288 GB
323.1 GB345.8 GB8-bit, near-lossless — 8-bit quantization, near-losslessRuns on 5× H100 SXM 80 GB
est.calculated, no published file yet

Selected Q4_K_M

4-bit medium quantization

205.2GBat 16K context

Weights
192.8 GB
KV cache
12.1 GB
Overhead
0.3 GB

Server-class: ~205.2 GB at 16K context · one Instinct MI325X 256 GB

Or rent B300 from $6.94/hr.

Which Hardware Can Run GLM 5.3 Flash?

Q4_K_M · 194.6 GB

GLM 5.3 Flash (Q4_K_M) requires 194.6 GB of VRAM to load the model weights. For comfortable inference with headroom for KV cache and system overhead, 253+ GB is recommended. Using the full 1049K context window can add up to 771.6 GB, bringing total usage to 966.2 GB. No consumer GPU has enough memory. 2 devices with unified memory can run GLM 5.3 Flash, including Mac Studio (M3 Ultra, 512GB), Mac Studio (M3 Ultra, 256GB).

By VRAM tier · typical GPUs and Macs at Q4_K_M

Consumer GPUs (up to 32 GB) and Macs up to 96 GB: too small for this model (needs ≥ 100.7 GB)8 GB tier →12 GB tier →16 GB tier →24 GB tier →Macs →

How good is GLM 5.3 Flash?

The llmrun Score merges 24 public benchmark boards into a single figure, where 100 represents the average for open models.

Score vs VRAM in the ≤256 GB tier

  • GLM 5.3 Flash
  • Other models
  • Best Score for its VRAM

#4 of 84 that fit ≤256 GB

Each dot is a model at the best quant that fits ≤256 GB. The line joins the models with the best Score for their VRAM; a dot below it is beaten by a model that needs no more memory.

Full ≤256 GB ranking →

Benchmarks

The 6 boards that weigh most in the llmrun Score, of 30 with a result for this model; badges show who ran the test.

In the ≤256 GB class

84 models fit ≤256 GB

Same Score, only models that fit ≤256 GB at their best quant: the ranking a ≤256 GB owner actually chooses from.

  1. #1

    131.9

    ~83 tok/s · 186.5 GB

  2. #2

    129.5

    ~45 tok/s · 210.4 GB

  3. #3

    127.6

    ~76 tok/s · 183.0 GB

  4. #4

    GLM 5.3 FlashZ.ai

    124.2

    ~83 tok/s · 205.2 GB

  5. #5

    122.9

    ~52 tok/s · 227.8 GB

  6. #6

    122.1

    ~207 tok/s · 17.9 GB

Alternatives to GLM 5.3 Flash

GLM 5 family · 6 models →

Official models with an llmrun Score, each answering one question; sizes are each model's default quant (usually Q4_K_M) with a 16K-token context.

Similar models

10
ModelScoreVRAMWhy it is similar
Qwen3.8 27BAlibaba122.117.9 GBsimilar score
Qwen3.5 397B A17BAlibaba113.0242.6 GBsimilar score
MiniMax M3MiniMax112.5258 GBsimilar score
MiniMax M2.5MiniMax111.8139.6 GBsimilar score
Qwen3.6 27BAlibaba111.217.9 GBsimilar score
NVIDIA Nemotron 3 Ultra 550B A55B BF16NVIDIA109.9378.4 GBsimilar score
DeepSeek V4 FlashDeepSeek109.3175.1 GBsimilar score
GLM 4.7Z.ai109.1217.9 GBsame size
MiMo V2.5Xiaomi108.3187.6 GBsame size
GLM 4.6Z.ai103.1216.9 GBsame size
Fine-tunes & variants(3)

Specifications

Publisher
Z.ai
Family
GLM 5
Parameters
321.3B
Active parameters
18.3B per token
Architecture
Glm5NextForConditionalGeneration
Context Length
1,048,576 tokens
Vocabulary Size
154,880
Release Date
2026-08-25
License
MIT

Frequently Asked Questions

How much VRAM does GLM 5.3 Flash need?

GLM 5.3 Flash requires 194.6 GB of VRAM at Q4_K_M, or 644.5 GB at BF16. Full 1049K context adds up to 771.6 GB (966.2 GB total).

VRAM = Weights + KV Cache + Overhead

Weights = 321.3B × 4.8 bits ÷ 8 = 192.8 GB

KV Cache + Overhead ≈ 1.8 GB (at 2K context + ~0.3 GB framework)

Fit ratings and hardware model lists check this model with room for a 16K-token context, which needs a little more memory.

KV Cache + Overhead ≈ 773.4 GB (at full 1049K context)

VRAM usage by quantization

194.6 GB
966.2 GB

Learn more about VRAM estimation →

Can NVIDIA GeForce RTX 5090 run GLM 5.3 Flash?

No — GLM 5.3 Flash requires at least 90.2 GB at IQ2_XXS, which exceeds the NVIDIA GeForce RTX 5090's 32 GB of VRAM.

What's the best quantization for GLM 5.3 Flash?

For GLM 5.3 Flash, Q4_K_M (194.6 GB) offers the best balance of quality and VRAM usage. Q5_K_M (230.8 GB) provides better quality if you have the VRAM. The smallest option is IQ2_XXS at 90.2 GB.

VRAM requirement by quantization

IQ2_XXS
90.2 GB
Q2_K
138.4 GB
IQ4_XS
174.5 GB
Q4_K_M ★
194.6 GB
Q6_K
266.9 GB
BF16
644.5 GB

★ Recommended — best balance of quality and VRAM usage.

Learn more about quantization →

Can I run GLM 5.3 Flash on a Mac?

Yes — Mac Pro M2 Ultra (128 GB) and 14 other Macs can run GLM 5.3 Flash, the smallest at IQ2_S. Apple Silicon uses unified memory, so the model shares RAM with the system. At Q4_K_M you need at least 194.6 GB of usable unified memory (RAM minus macOS overhead), from Mac Studio (M3 Ultra, 256GB).

Can I run GLM 5.3 Flash locally?

Yes — GLM 5.3 Flash can run locally on consumer hardware. Popular tools include Ollama, LM Studio, and llama.cpp.

How fast is GLM 5.3 Flash?

At Q4_K_M, GLM 5.3 Flash can reach ~88 tok/s on AMD Instinct MI350X. Speed depends mainly on GPU memory bandwidth. Real-world results typically within ±20%.

tok/s = 1000 ÷ (active GB ÷ (bandwidth GB/s × efficiency) × 1000 + layers × routing ms)

Mixture-of-Experts: just the active experts get read for each token, along with a fixed routing cost per layer.

Example: NVIDIA B300 → 11.1 GB active ÷ (8000 × 0.65) = 2.13 ms, plus 45 layers × 0.055 ms = 2.48 ms, so 1000 ÷ 4.61 ms = ~217 tok/s

Estimated speed at Q4_K_M (194.6 GB)

~217 tok/s
~88 tok/s
~88 tok/s

Real-world results typically within ±20%. Speed depends on batch size, quantization kernel, and software stack.

Learn more about tok/s estimation →

What's the download size of GLM 5.3 Flash?

At Q4_K_M, the download is about 192.79 GB. The full-precision BF16 version is 642.65 GB. The smallest option (IQ2_XXS) is 88.36 GB.

Which GPUs can run GLM 5.3 Flash?

No single consumer GPU has enough VRAM to run GLM 5.3 Flash at Q4_K_M (194.6 GB). Multi-GPU or professional hardware is required.

Which devices can run GLM 5.3 Flash?

2 devices with unified memory can run GLM 5.3 Flash at Q4_K_M (194.6 GB), including Mac Studio (M3 Ultra, 256GB), Mac Studio (M3 Ultra, 512GB). Apple Silicon Macs use unified memory shared between CPU and GPU, making them well-suited for local LLM inference.