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GLM / MoE

GLM-5.3-Flash

Smaller than GLM-5.3, still a multi-GPU model

Release noteSources checked 2026-09-13

This is the GLM candidate to examine when you need native visual input and a smaller active path than the flagship. Its 320B store remains large; the useful starting point is a documented four-GPU FP8 recipe.

320Breported total parameters
18Bactive parameters per token
1,048,576configured token positions

Publisher-reported, rounded model count; not an exact tensor census. Multimodal components and packaging can change the artifact size.

Evaluate it for

Visual coding agents and long-context multimodal services with compatible kernels.

Choose another path when

Older serving images, Hopper FP8-KV assumptions copied from another model, or a device budget based on GLM-4.7-Flash.

Release context

Why this release matters

The model combines Kimi Delta Attention with sparse latent attention and index pooling. Supporting those operators matters more than whether a server can merely load an FP8 tensor file.

This is the dated Z.ai release-note event; a separate first weight-upload day has not been certified.

Release evidence · Follow the GLM timeline →

Deployment starting points

Which hardware, how many, at what precision?

Start with an exact artifact and an engine that supports it. A configuration below is evidence of a documented path; its device count does not promise a particular throughput or concurrency.

Runtime recipe

4 × GB200 GPUs

GPUs within an NVLink system; this is not a count of whole racks.

FP8 weights

vLLM 0.29 model guide

One four-GPU GB200 tray. Requires the sparse-MLA/KDA kernels; FP8 KV and MTP are separate configuration choices.

Checkpoint and source

zai-org/GLM-5.3-Flash

Checked 2026-09-13. Read the documented setup →

Hardware specifications and interconnect →

328.33 GB of tensor data in the pinned index

This is the index’s reported tensor payload, in decimal GB. It excludes file headers and runtime memory. Mixed precision, conversion and host/device placement determine how much GPU memory the loaded model needs.

Inspect the exact index metadata →
Capacity screen: would the weights fit?

This estimates inference memory for a hypothetical uniform precision. It is useful for rejecting an allocation that is too small. It does not establish a working deployment or estimate training memory.

A uniform-precision GPU count would hide this model’s component layout. Publisher-reported, rounded model count; not an exact tensor census. Multimodal components and packaging can change the artifact size. Use the documented artifact and placement path above; no GPU count is inferred here.

Architecture in practice

What the serving engine has to do

Two kinds of layers retain two kinds of state.

A token enters a layerthe layer type selects its pathRecurrent layerupdate a compact stateAttention layerread retained token historyRecurrent statemaintained for this sequenceAttention cachelayout depends on the model

Hybrid attention does not mean zero request state.

A full-attention formula cannot describe every layer.

Schematic of a hybrid attention stack, not a literal layer ordering. Recurrent layers update a compact state; attention layers retain their own history. Both kinds of state matter for prefix reuse and concurrent requests.

Mechanism schematic based on the pinned model card and configuration. It explains a design principle; it is not a full implementation graph.

Inspect the full checkpoint specifications
Inspected fields for this exact revision. KV heads alone do not describe latent, hybrid or shared-cache layouts.
Exact checkpointzai-org/GLM-5.3-Flash
Text model typeglm5_next_text
Layers45
Hidden width4,096
Attention / KV heads64 / 64
Head dimensionNot verified
Routed / selected experts288 / 8
Configured positions1,048,576
Documented extensionNot recorded for this checkpoint
Inputs → outputtext, image, video → text
License metadatamit

34 linear attention layers; 11 deepseek sparse attention layers. These counts describe the configured pattern.

Open weights do not imply unrestricted use. Read the applicable license terms linked from the pinned card.

A useful comparison

What else belongs on the shortlist?

The flagship is the text-focused quality comparison; Qwen’s Flash-Next offers a different conditional-memory tradeoff.

14 Aug 2026

GLM-5.3

A post-training release with a changed adoption decision

743B reported total · text

26 Aug 2026

Qwen3.8-Flash-Next

The memory placement is part of the architecture

180B reported total · text + image + video

These are editorial comparison candidates. We have not run a matched quality or serving benchmark, so this is not a ranking.

Prepare to explain it

The interview lesson

Explain the hybrid state split and the difference between FP8 weights, FP8 KV and Blackwell-only NVFP4 paths.

Attention layouts · Quantization · Courses and worked examples

For a deployment evaluation, record exact weights, precision, engine, device count, interconnect, prompt/output lengths and concurrency. Report task success, errors, TTFT, TPOT and useful throughput together.

Sources and citation

Our assessment is editorial judgment based on the linked architecture and deployment evidence. Model facts are publisher-reported or attributed to runtime maintainers; no independent GPU benchmark was run.

AI Infra Interviews, “GLM-5.3-Flash: release, architecture and deployment”, checked 2026-09-13. Preserve this date and the exact checkpoint when citing.

Model and research notes as JSON · Z.ai profile