GLM 5.3 Flash VRAM, RAM and GPU requirements (256K context)

The short answer

At 256K context you need a 192 GB DDR5 kit for Q4 (with one or two 24–32 GB cards) and 256 GB for Q5 on one card or Q6 on two R9700s. Expect single-digit to about 10 tokens per second on a desktop (estimate, not yet measured on the local desktop). If you do not specifically need GLM, Qwen 3.8 Flash at Q4 on two R9700s runs at 256K in a 96 GB kit, faster, for much less RAM.

RAM kit needed at 262,144 context (estimate)

Hugging Face file sizes, tensor groups from the GGUF headers, and the attention cache from the official config (only 11 of 45 layers keep a growing cache, so 256K costs about 5 GiB at f16). Assumes llama.cpp with experts offloaded to RAM. All estimates until a host-RAM run card exists. Q3 and below are not covered.

How fast? (estimate)

The token rate is set by how fast your RAM feeds the experts, not by the GPU. A bandwidth model puts two R9700s with DDR5 at a ceiling of about 10.7 / 8.8 / 7.1 tok/s for Q4 / Q5 / Q6. Real llama.cpp runs usually land well under the ceiling (about 4–7 tok/s for Q4 on a 192 GB, 4-stick kit). Four sticks on AM5 also run slower than two (AMD lists DDR5-3600 with 4 DIMMs vs 5600 with 2). Measured numbers will replace these when we have them on the local desktop.

Is GLM 5.3 Flash worth the RAM?

Buy for GLM only if you want this specific model (for example its MIT-style license, see its Hugging Face card) and accept slow output. For a fast daily driver, the 35B on one R9700 (about 100 tok/s measured on the local desktop) or Qwen 3.8 Flash on two R9700s (96 GB) gets far more done. More RAM buys a bigger, smarter, much slower model.

• Flash at 96 GB
• 35B at 32 GB VRAM

Buy-nothing paths

Already have 128 GB? GLM at Q4+ will not fit at 256K; run Qwen 3.8 Flash UD-Q5 on two cards instead. Use a hosted GLM API for occasional long jobs and keep the desktop on the 35B. Strix Halo cannot run GLM at Q4+: its memory is soldered (max 128 GB) and the Q4 weights alone are 186 GiB.

• GLM model page
• Strix Halo

Most readers should buy 96 GB for Qwen Flash instead

A 192 GB or 256 GB kit is the GLM path. We omit street prices unless we read the listing today. Most builds should stay on 96 GB DDR5 and Qwen 3.8 Flash Q4. Check current 192 GB kits only if you already know you want this model.

Check 192 GB kits at Newegg

FAQ

How much VRAM does GLM 5.3 Flash need?

Any 16 GB+ card works as the attention-and-shared GPU; the experts go to system RAM. More VRAM only trims the RAM need (about 28 GiB less from one R9700 to two).

GLM requirements

How much RAM for GLM 5.3 Flash?

192 GB for Q4 at 256K, 256 GB for Q5 on one card or Q6 on two cards. Estimates. Not measured on the local desktop.

Calculator

Can Strix Halo run GLM 5.3 Flash?

Not at Q4 or above: its 128 GB is soldered and the Q4 weights alone are 186 GiB.

Strix Halo

Can I run it with 16 GB VRAM?

Yes at Q4 with a 256 GB kit, slowly. Estimate only.

Can my Radeon run it?

Sources

• S-HF — zai-org/GLM-5.3-Flash model card — third-party · checked 2026-11-02 · read 2026-11-02
• S-GGUF — unsloth/GLM-5.3-Flash-GGUF — UD-Q4_K_XL 186.0 GiB — third-party · checked 2026-11-02 · 199.71 decimal GB listing = 186.0 GiB
• S-CALC — AMDai calculator RAM kits at 262K — our lab · checked 2026-11-02 · site calculator; KV ~5 GiB at 256K f16 (11 of 45 layers keep a growing cache)