Llama 3.1 405B Instruct vs Qwen3.8 27B

Qwen3.8 27B leads llmrun Score 122.1 to 83.2; only Qwen3.8 27B fits 24 GB (Q4_K_M); Llama 3.1 405B Instruct needs 197.4 GB even at its smallest quant.

Model A · Meta

Llama 3.1 405B Instruct

83.2llmrun Score

405.9B · Llama 3.1 Community · Jul 2024

ChatFunctions

Model B · Alibaba

Qwen3.8 27B

122.1llmrun Score

27.8B · 256K context · Apache 2.0 · Aug 2026

VisionFunctions

Which should you choose?

Choose Llama 3.1 405B Instruct if you want…

Also does chat
Qwen3.8 27B doesn't list it

Choose Qwen3.8 27B if you want…

Higher llmrun Score
122.1 vs 83.2
Stronger at reasoning
124.0 vs 85.0
Fits a 12 GB GPU
IQ3_XXS · 12 GB; Llama 3.1 405B Instruct needs 197.4 GB at its smallest quant
Fits a Mac 32 GB
Q4_K_M · 17.9 GB; Llama 3.1 405B Instruct needs 197.4 GB at its smallest quant
Lighter on memory
17.4 vs 267.9 GB at Q4_K_M
Also does vision
Llama 3.1 405B Instruct doesn't list it

On your hardware

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

MemoryLlama 3.1 405B InstructQwen3.8 27B

8 GB

RTX 4060 · 8 GB tier

Llama 3.1 405B Instruct

Doesn't fit

smallest quant needs 197.4 GB

Qwen3.8 27B

Doesn't fit

smallest quant needs 8.8 GB

12 GB

RTX 3060 12GB · 12 GB tier

Llama 3.1 405B Instruct

Doesn't fit

smallest quant needs 197.4 GB

Qwen3.8 27B

IQ3_XXS · ~20 tok/s

12 GB · up to 16Kfits

16 GB

RTX 5060 Ti 16GB · 16 GB tier

Llama 3.1 405B Instruct

Doesn't fit

smallest quant needs 197.4 GB

Qwen3.8 27B

Q3_K_L · ~19 tok/s

15.4 GB · up to 16Kfits

24 GBreference

RTX 4090 · 24 GB tier

Llama 3.1 405B Instruct

Doesn't fit

smallest quant needs 197.4 GB

Qwen3.8 27B

Q4_K_M · ~38 tok/s

17.9 GB · up to 64Kfits

32 GB

RTX 5090 · 32 GB tier

Llama 3.1 405B Instruct

Doesn't fit

smallest quant needs 197.4 GB

Qwen3.8 27B

Q4_K_M · ~67 tok/s

17.9 GB · up to 256Kfits

48 GB

RTX A6000 · 48 GB tier

Llama 3.1 405B Instruct

Doesn't fit

smallest quant needs 197.4 GB

Qwen3.8 27B

Q4_K_M · ~29 tok/s

17.9 GB · up to 256Kfits

Mac 32 GB

Mac Mini M4 · Macs

Llama 3.1 405B Instruct

Doesn't fit

smallest quant needs 197.4 GB

Qwen3.8 27B

Q4_K_M · ~5 tok/s

17.9 GB · up to 128Kfits

Mac 64 GB

Mac Studio M4 Max · Macs

Llama 3.1 405B Instruct

Doesn't fit

smallest quant needs 197.4 GB

Qwen3.8 27B

Q4_K_M · ~22 tok/s

17.9 GB · up to 256Kfits

Mac 128 GB

Mac Studio M4 Max · Macs

Llama 3.1 405B Instruct

Doesn't fit

smallest quant needs 197.4 GB

Qwen3.8 27B

Q4_K_M · ~22 tok/s

17.9 GB · up to 256Kfits

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

Llama 3.1 405B Instruct Qwen3.8 27B

Overall

Llama 3.1 405B Instruct

83.279–87

Qwen3.8 27B

122.1120–124

Coding

Llama 3.1 405B Instruct

no data

Qwen3.8 27B

119.7114–125

Agents

Llama 3.1 405B Instruct

no data

Qwen3.8 27B

122.8117–129

Math

Llama 3.1 405B Instruct

no data

Qwen3.8 27B

117.5111–124

Science

Llama 3.1 405B Instruct

no data

Qwen3.8 27B

112.093–131

Reasoning

Llama 3.1 405B Instruct

85.077–93

Qwen3.8 27B

124.0121–127

Llama 3.1 405B Instruct · #76 of 100 open models · #73 of 96 that fit ≤512 GB

Qwen3.8 27B · #11 of 100 open models · #1 of 35 that fit 24 GB

Benchmarks

1 shared board: Llama 3.1 405B Instruct leads 0, Qwen3.8 27B leads 1 · Benchmarks imported Oct 2026

BoardLlama 3.1 405B InstructQwen3.8 27B

DTBench

Llama 3.1 405B Instruct

61.4%#42/68 open

Lab-reportedEpoch AI · Jul 2024

Qwen3.8 27B

88.0%#9/68 open

Lab-reportedEpoch AI · Aug 2026

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

LMArena Text

Llama 3.1 405B Instruct

1335.5#86/187 open

ArenaLMArena · Oct 2026

Qwen3.8 27B

1437.8#22/187 open

ArenaLMArena · Oct 2026

Only Llama 3.1 405B Instruct (9)

Only Qwen3.8 27B (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.

QuantLlama 3.1 405B InstructQwen3.8 27B

Q2_K

Llama 3.1 405B Instruct

190 GB151.2 GB file

32K 206 GB · 128K 259 GB

Qwen3.8 27B

12.6 GB10.8 GB file

32K 13.9 GB · 128K 19.3 GB

Q3_K_S

Llama 3.1 405B Instruct

195 GB177.1 GB file

32K 212 GB · 128K 265 GB

Qwen3.8 27B

12.9 GB12.7 GB file

32K 14.2 GB · 128K 19.6 GB

Q3_K_M

Llama 3.1 405B Instruct

218 GB~197.8 GB file

32K 234 GB · 128K 287 GB

Qwen3.8 27B

14.3 GB13.4 GB file

32K 15.6 GB · 128K 21.0 GB

Q4_0

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

14.6 GB~13.9 GB file

32K 16.0 GB · 128K 21.4 GB

Q4_K_M

Llama 3.1 405B Instruct

268 GB~243.5 GB file

32K 284 GB · 128K 337 GB

Qwen3.8 27B

17.4 GB16.5 GB file

32K 18.8 GB · 128K 24.1 GB

Q5_K_M

Llama 3.1 405B Instruct

318 GB~289.2 GB file

32K 335 GB · 128K 387 GB

Qwen3.8 27B

20.5 GB19.8 GB file

32K 21.9 GB · 128K 27.3 GB

Q6_K

Llama 3.1 405B Instruct

368 GB~334.8 GB file

32K 385 GB · 128K 438 GB

Qwen3.8 27B

23.7 GB22.0 GB file

32K 25.0 GB · 128K 30.4 GB

Q8_0

Llama 3.1 405B Instruct

446 GB~405.9 GB file

32K 463 GB · 128K 516 GB

Qwen3.8 27B

28.5 GB29.0 GB file

32K 29.9 GB · 128K 35.2 GB

17 more quants

IQ2_XXS

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

8.4 GB7.3 GB file

32K 9.7 GB · 128K 15.1 GB

IQ2_XS

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

9.1 GB9.1 GB file

32K 10.4 GB · 128K 15.8 GB

IQ2_S

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

9.4 GB8.4 GB file

32K 10.8 GB · 128K 16.1 GB

IQ2_M

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

10.1 GB10.5 GB file

32K 11.5 GB · 128K 16.8 GB

IQ3_XXS

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

11.5 GB10.9 GB file

32K 12.9 GB · 128K 18.2 GB

IQ3_XS

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

12.2 GB10.4 GB file

32K 13.6 GB · 128K 18.9 GB

IQ3_S

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

12.6 GB12.0 GB file

32K 13.9 GB · 128K 19.3 GB

IQ3_M

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

13.3 GB14.9 GB file

32K 14.6 GB · 128K 20.0 GB

Q3_K_L

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

15.0 GB14.1 GB file

32K 16.3 GB · 128K 21.7 GB

IQ4_XS

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

15.7 GB14.3 GB file

32K 17.0 GB · 128K 22.4 GB

IQ4_NL

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

16.4 GB17.4 GB file

32K 17.7 GB · 128K 23.1 GB

Q4_1

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

16.4 GB17.5 GB file

32K 17.7 GB · 128K 23.1 GB

Q4_K_S

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

16.4 GB15.4 GB file

32K 17.7 GB · 128K 23.1 GB

Q4_K_L

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

17.8 GB18.8 GB file

32K 19.1 GB · 128K 24.5 GB

Q5_K_S

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

19.9 GB18.7 GB file

32K 21.2 GB · 128K 26.6 GB

Q5_K_L

Llama 3.1 405B Instruct

not listed

Qwen3.8 27B

20.9 GB21.5 GB file

32K 22.2 GB · 128K 27.6 GB

BF16

Llama 3.1 405B Instruct

893 GB~811.7 GB file

32K 909 GB · 128K 962 GB

Qwen3.8 27B

56.3 GB54.7 GB file

32K 57.7 GB · 128K 63.0 GB

How to run each

Llama 3.1 405B Instruct

Ollama · Q4_K_M

$ollama run hf.co/MaziyarPanahi/Meta-Llama-3.1-405B-Instruct-GGUF

All ways to run Llama 3.1 405B Instruct →

Qwen3.8 27B

Ollama · Q4_K_M

$ollama run hf.co/unsloth/Qwen3.8-27B-GGUF:Q4_K_M

All ways to run Qwen3.8 27B →

Specifications

Specifications of Llama 3.1 405B Instruct and Qwen3.8 27B
Spec	Llama 3.1 405B Instruct	Qwen3.8 27B
Publisher	Meta	Alibaba
Parameters	405.9B	27.8B
Architecture	—	Qwen3_5ForConditionalGeneration
Context	—	256K tokens
Modalities	Chat, Function-calling	Vision, Function-calling
License	Llama 3.1 Community	Apache 2.0
Released	Jul 2024	Aug 2026

Frequently Asked Questions

Which is better, Llama 3.1 405B Instruct or Qwen3.8 27B?

Qwen3.8 27B leads llmrun Score 122.1 to 83.2; only Qwen3.8 27B fits 24 GB (Q4_K_M); Llama 3.1 405B Instruct needs 197.4 GB even at its smallest quant. Choose Llama 3.1 405B Instruct for also does chat; choose Qwen3.8 27B for higher llmrun Score and stronger at reasoning.

Which needs less VRAM, Llama 3.1 405B Instruct or Qwen3.8 27B?

At Q4_K_M, Llama 3.1 405B Instruct requires 267.9 GB while Qwen3.8 27B needs 17.4 GB, making Qwen3.8 27B the easier model to run on your local setup.

Can I run Llama 3.1 405B Instruct or Qwen3.8 27B on a 16 GB GPU?

Llama 3.1 405B Instruct does not fit (smallest quant needs 197.4 GB); Qwen3.8 27B fits at Q3_K_L.