GLM 5.1 vs GLM 5.3 Flash

GLM 5.3 Flash leads llmrun Score 124.2 to 117.8; neither fits 24 GB.

Model A · Z.ai

GLM 5.1

117.8llmrun Score

753.9B · 42.4B active · 198K context · MIT · Apr 2026

ChatFunctions

Model B · Z.ai

GLM 5.3 Flash

124.2llmrun Score

321.3B · 18.3B active · 1M context · MIT · Aug 2026

VisionFunctions

Which should you choose?

Choose GLM 5.1 if you want…

Also does chat
GLM 5.3 Flash doesn't list it

Choose GLM 5.3 Flash if you want…

Higher llmrun Score
124.2 vs 117.8
Stronger at reasoning
127.4 vs 115.6
Stronger at science
123.7 vs 116.8
Ahead on the benchmarks
6 of 9 shared boards
Lighter on memory
194.6 vs 456.5 GB at Q4_K_M
Longer context window
1M vs 198K tokens

On your hardware

Each model at its default quant (Q4_K_M), a smaller one when it must. Estimates, ±20%.

MemoryGLM 5.1GLM 5.3 Flash

8 GB

RTX 4060 · 8 GB tier

GLM 5.1

Doesn't fit

smallest quant needs 209.1 GB

GLM 5.3 Flash

Doesn't fit

smallest quant needs 100.7 GB

12 GB

RTX 3060 12GB · 12 GB tier

GLM 5.1

Doesn't fit

smallest quant needs 209.1 GB

GLM 5.3 Flash

Doesn't fit

smallest quant needs 100.7 GB

16 GB

RTX 5060 Ti 16GB · 16 GB tier

GLM 5.1

Doesn't fit

smallest quant needs 209.1 GB

GLM 5.3 Flash

Doesn't fit

smallest quant needs 100.7 GB

24 GBreference

RTX 4090 · 24 GB tier

GLM 5.1

Doesn't fit

smallest quant needs 209.1 GB

GLM 5.3 Flash

Doesn't fit

smallest quant needs 100.7 GB

32 GB

RTX 5090 · 32 GB tier

GLM 5.1

Doesn't fit

smallest quant needs 209.1 GB

GLM 5.3 Flash

Doesn't fit

smallest quant needs 100.7 GB

48 GB

RTX A6000 · 48 GB tier

GLM 5.1

Doesn't fit

smallest quant needs 209.1 GB

GLM 5.3 Flash

Doesn't fit

smallest quant needs 100.7 GB

Mac 32 GB

Mac Mini M4 · Macs

GLM 5.1

Doesn't fit

smallest quant needs 209.1 GB

GLM 5.3 Flash

Doesn't fit

smallest quant needs 100.7 GB

Mac 64 GB

Mac Studio M4 Max · Macs

GLM 5.1

Doesn't fit

smallest quant needs 209.1 GB

GLM 5.3 Flash

Doesn't fit

smallest quant needs 100.7 GB

Mac 128 GB

Mac Studio M4 Max · Macs

GLM 5.1

Doesn't fit

smallest quant needs 209.1 GB

GLM 5.3 Flash

IQ2_S · ~41 tok/s

112.8 GB · up to 16Kfits

Reference GPU: RTX 4090. Tinted cell = the better pick on that machine (fits, more headroom, or at least 10% faster).

llmrun Score

with its 90% range · bars share one scale

GLM 5.1 GLM 5.3 Flash

Overall

GLM 5.1

117.8115–121

GLM 5.3 Flash

124.2122–126

Coding

GLM 5.1

114.5107–122

GLM 5.3 Flash

117.4113–122

Agents

GLM 5.1

122.7116–129

GLM 5.3 Flash

127.4124–131

Math

GLM 5.1

117.4113–122

GLM 5.3 Flash

121.4118–125

Science

GLM 5.1

116.8106–127

GLM 5.3 Flash

123.7112–135

Reasoning

GLM 5.1

115.6105–126

GLM 5.3 Flash

127.4124–130

GLM 5.1 · #15 of 100 open models · #13 of 96 that fit ≤512 GB

GLM 5.3 Flash · #9 of 100 open models · #4 of 84 that fit ≤256 GB

Benchmarks

9 shared boards: GLM 5.1 leads 2, GLM 5.3 Flash leads 6 · Benchmarks imported Oct 2026

BoardGLM 5.1GLM 5.3 Flash

GPQA Diamond

GLM 5.1

89.9%#10/98 open

IndependentEpoch AI · Apr 2026

GLM 5.3 Flash

90.1%#9/98 open

IndependentEpoch AI · Aug 2026

AIME 2024/2025

GLM 5.1

93.3%#10/86 open

IndependentEpoch AI · Apr 2026

GLM 5.3 Flash

93.9%#9/86 open

IndependentEpoch AI · Aug 2026

FrontierMath

GLM 5.1

36.8%#13/17 open

IndependentEpoch AI · Apr 2026

GLM 5.3 Flash

55.8%#9/17 open

IndependentEpoch AI · Aug 2026

SciCode

GLM 5.1

44.8%#25/66 open

Lab-reportedEpoch AI · Apr 2026

GLM 5.3 Flash

51.6%#6/66 open

Lab-reportedEpoch AI · Aug 2026

ALE-Bench

GLM 5.1

887.1#15/43 open

Lab-reportedEpoch AI · Apr 2026

GLM 5.3 Flash

303.6#39/43 open

Lab-reportedEpoch AI · Aug 2026

APEX-Agents

GLM 5.1

40.9%#8/16 open

Lab-reportedEpoch AI · Apr 2026

GLM 5.3 Flash

52.8%#3/16 open

Lab-reportedEpoch AI · Aug 2026

Chess Puzzles

GLM 5.1

20.0%#11/14 open

IndependentEpoch AI · Apr 2026

GLM 5.3 Flash

21.0%#9/14 open

IndependentEpoch AI · Aug 2026

CritPt

GLM 5.1

4.6%#17/66 open

Lab-reportedEpoch AI · Apr 2026

GLM 5.3 Flash

15.4%#7/66 open

Lab-reportedEpoch AI · Aug 2026

ProofBench

GLM 5.1

22.2%#10/26 open

Lab-reportedEpoch AI · Apr 2026

GLM 5.3 Flash

21.0%#12/26 open

Lab-reportedEpoch AI · Aug 2026

26 more boards (other shared and single-model boards)

LMArena Text

GLM 5.1

1465.2#8/187 open

ArenaLMArena · Oct 2026

GLM 5.3 Flash

1473.8#6/187 open

ArenaLMArena · Oct 2026

LMArena WebDev

GLM 5.1

1508.5#15/52 open

ArenaLMArena · Oct 2026

GLM 5.3 Flash

1605.5#8/52 open

ArenaLMArena · Oct 2026

Only GLM 5.1 (5)

Only GLM 5.3 Flash (19)

VRAM by quantization

Memory to load the model and 2K context; below it, the total at 32K and 128K context. Lighter side in bold.

QuantGLM 5.1GLM 5.3 Flash

Q2_K

GLM 5.1

325 GB265.8 GB file

32K 324 GB · 128K 332 GB

GLM 5.3 Flash

138 GB114.2 GB file

32K 161 GB · 128K 234 GB

Q3_K_S

GLM 5.1

334 GB313.5 GB file

32K 333 GB · 128K 342 GB

GLM 5.3 Flash

not listed

Q3_K_M

GLM 5.1

372 GB338.4 GB file

32K 371 GB · 128K 380 GB

GLM 5.3 Flash

158 GB149.1 GB file

32K 181 GB · 128K 254 GB

Q4_0

GLM 5.1

381 GB427.6 GB file

32K 380 GB · 128K 389 GB

GLM 5.3 Flash

not listed

Q4_K_M

GLM 5.1

457 GB464.5 GB file

32K 456 GB · 128K 464 GB

GLM 5.3 Flash

195 GB188.7 GB file

32K 217 GB · 128K 290 GB

Q5_K_M

GLM 5.1

541 GB558.5 GB file

32K 540 GB · 128K 549 GB

GLM 5.3 Flash

231 GB~228.9 GB file

32K 253 GB · 128K 326 GB

Q6_K

GLM 5.1

626 GB621.3 GB file

32K 625 GB · 128K 634 GB

GLM 5.3 Flash

267 GB~265.1 GB file

32K 290 GB · 128K 362 GB

Q8_0

GLM 5.1

758 GB801.3 GB file

32K 757 GB · 128K 766 GB

GLM 5.3 Flash

323 GB341.0 GB file

32K 346 GB · 128K 418 GB

16 more quants

IQ2_XXS

GLM 5.1

212 GB220.6 GB file

32K 211 GB · 128K 219 GB

GLM 5.3 Flash

90.2 GB101.8 GB file

32K 113 GB · 128K 185 GB

IQ2_XS

GLM 5.1

230 GB226.6 GB file

32K 229 GB · 128K 238 GB

GLM 5.3 Flash

not listed

IQ2_S

GLM 5.1

240 GB231.4 GB file

32K 239 GB · 128K 248 GB

GLM 5.3 Flash

102 GB113.6 GB file

32K 125 GB · 128K 197 GB

IQ2_M

GLM 5.1

259 GB236.2 GB file

32K 258 GB · 128K 267 GB

GLM 5.3 Flash

not listed

IQ3_XXS

GLM 5.1

296 GB268.3 GB file

32K 295 GB · 128K 304 GB

GLM 5.3 Flash

126 GB120.4 GB file

32K 149 GB · 128K 221 GB

IQ3_XS

GLM 5.1

315 GB343.9 GB file

32K 314 GB · 128K 323 GB

GLM 5.3 Flash

not listed

IQ3_S

GLM 5.1

325 GB279.6 GB file

32K 324 GB · 128K 332 GB

GLM 5.3 Flash

not listed

IQ3_M

GLM 5.1

343 GB360.3 GB file

32K 342 GB · 128K 351 GB

GLM 5.3 Flash

not listed

Q3_K_L

GLM 5.1

391 GB358.9 GB file

32K 390 GB · 128K 398 GB

GLM 5.3 Flash

not listed

IQ4_XS

GLM 5.1

409 GB361.3 GB file

32K 408 GB · 128K 417 GB

GLM 5.3 Flash

175 GB156.8 GB file

32K 197 GB · 128K 270 GB

IQ4_NL

GLM 5.1

428 GB368.9 GB file

32K 427 GB · 128K 436 GB

GLM 5.3 Flash

not listed

Q4_1

GLM 5.1

428 GB472.7 GB file

32K 427 GB · 128K 436 GB

GLM 5.3 Flash

not listed

Q4_K_S

GLM 5.1

428 GB433.9 GB file

32K 427 GB · 128K 436 GB

GLM 5.3 Flash

not listed

Q4_K_L

GLM 5.1

466 GB460.4 GB file

32K 465 GB · 128K 474 GB

GLM 5.3 Flash

not listed

Q5_K_S

GLM 5.1

523 GB525.9 GB file

32K 522 GB · 128K 530 GB

GLM 5.3 Flash

not listed

BF16

GLM 5.1

1512 GB1508.0 GB file

32K 1511 GB · 128K 1520 GB

GLM 5.3 Flash

644 GB641.6 GB file

32K 667 GB · 128K 740 GB

How to run each

GLM 5.1

Ollama · Q4_K_M

$ollama run hf.co/unsloth/GLM-5.1-GGUF:Q4_K_M

All ways to run GLM 5.1 →

GLM 5.3 Flash

Ollama · Q4_K_M

$ollama run hf.co/batiai/GLM-5.3-Flash-GGUF:Q4_K_M

All ways to run GLM 5.3 Flash →

Specifications

Specifications of GLM 5.1 and GLM 5.3 Flash
Spec	GLM 5.1	GLM 5.3 Flash
Publisher	Z.ai	Z.ai
Parameters	753.9B	321.3B
Active parameters	42B per token	18B per token
Architecture	GlmMoeDsaForCausalLM	Glm5NextForConditionalGeneration
Context	198K tokens	1M tokens
Modalities	Chat, Function-calling	Vision, Function-calling
License	MIT	MIT
Released	Apr 2026	Aug 2026

Frequently Asked Questions

Which is better, GLM 5.1 or GLM 5.3 Flash?

GLM 5.3 Flash leads llmrun Score 124.2 to 117.8; neither fits 24 GB. Choose GLM 5.1 for also does chat; choose GLM 5.3 Flash for higher llmrun Score and stronger at reasoning.

Which needs less VRAM, GLM 5.1 or GLM 5.3 Flash?

At Q4_K_M, GLM 5.1 requires 456.5 GB while GLM 5.3 Flash needs 194.6 GB, making GLM 5.3 Flash the easier model to run on your local setup.

Can I run GLM 5.1 or GLM 5.3 Flash on a 16 GB GPU?

GLM 5.1 does not fit (smallest quant needs 209.1 GB); GLM 5.3 Flash does not fit (smallest quant needs 100.7 GB).

Which has a longer context window, GLM 5.1 or GLM 5.3 Flash?

GLM 5.1 supports 202,752 tokens and GLM 5.3 Flash supports 1,048,576 tokens.