Updated September 2026

RTX 4090 24GB Anything that fits into 24GB is fast. The limit is also exactly 24GB.

This is the machine to look at if you want to quickly process LLM and image creation that fit in 24GB and avoid the new high price.

Speed and memory for the same model

RTX 4090 24GB · Qwen3.8 27B · local LLM speed and memory: Prompt processing · prefill 1,141–1,591 tok/s · Token generation · decode 38.3–51.9 tok/s; Required 17.56GB / Usable 22.5GB VRAM
4,096 input tokens · single request · prompt cache off

Hardware core specifications

Available memory
22.5GB
Memory bandwidth
1008GB/s
Estimated sustained LLM load
About 470W
Korean price range (KRW)
325 × KRW 10,000–400 × KRW 10,000

Who it fits

  • Fast 12B to 27B inference
  • ComfyUI image generation
  • CUDA development environment

Skip it if

Models with more than 24GB cannot be loaded even if they are fast, and their appeal diminishes if used prices are close to the 5090.

Recommended format for each device 4K input

The model you will experience with this equipment

K2 Horizon 0.9B

Required 1.03GB · spare time

llama.cpp CUDA · Q4_K_M

Decode

1426.4 ~ 1578.6 tok/s

First token

0.16 to 0.22 seconds

Qwen3.8 27B

recommended

Required 17.56GB · titration

llama.cpp CUDA · Q4_K_M

Decode

38.3 ~ 51.9 tok/s

First token

2.6 to 3.6 seconds

speed tuning

Qwen3.8-Flash-Next

Required 74.5561152GB · tight

Strata 0.1.33 serving branch · IQ3_S · MTP-4 · INT8 KV · SSD PLE

Decode

92.6 ~ 192.3 tok/s

First token

0.72 to 1.5 seconds

speed tuning

Actual speed varies with runtime version, cooling, context length and quantization file.

purchase judgment

What tasks is it suitable for?

27B conversation

comfortable

High single GPU speed within 24GB.

Create image

comfortable

Compare the processing speed of the same model together with our support tools.

large model

Conditional

If you exceed VRAM, CPU/RAM offloading loss is significant.

The first thing to get stuck
The 24GB VRAM limit is reached before compute performance.
Configuration to check
RTX 4090 24GB · System RAM 64GB · 1000W power · 4 slots available
Criteria for spending more money
It's worth it when the price difference over the 5090 is big enough and 24GB is enough. If you need 32GB, look no further than the 5090.

On sales pages, look at memory before chips.

The model and speed assumptions above change if the product is not the 24GB configuration.

Frequently asked questions

What LLM can be run on an RTX 4090 24GB?
K2 Horizon 0.9B, Qwen3.8 27B, Qwen3.8-Flash-Next and others with a 4K input and the recommended format. Required memory varies by model and context length.
What is the power consumption of a local LLM on an RTX 4090 with 24GB?
Sustained load is about 470 W, with an actual range of 350–600 W.
Are the displayed token speeds ground truth?
This is a range aligned to collected benchmark measurements under the same conditions. Combinations without a matching measurement are estimated from the nearest result and vary with runtime, cooling, quantization file and context length.