Can Qwen 2.5 72B run on RTX 4000 Ada 20GB?

NO — Won't Fit

F0Won't run

Estimated from fit model

Qwen 2.5 72B needs ~52.0 GB but RTX 4000 Ada 20GB only has 20.0 GB. Try a smaller quantization or lighter model.

Runtime: OllamaCapacity: No fitBandwidth: LowStack: BasicBottleneck: Memory capacity

Operating mode

Choose the run profile you care about

Interactive favors responsiveness, while light API and scale-out lean harder on serving readiness. The fit stays the same, but the recommendation lens changes.

Current mode

Balanced

Balanced for general local use. Keeps the ranking neutral across personal and serving workflows.

Capabilities:

Select quantization to explore

Q4_K_M (Medium quality) — 52.0 GB, exceeds 20.0 GB available

52.0 GB required20.0 GB available

260% VRAM needed

32.0 GB over capacity — needs offload or smaller quantization

Fit status

Too heavy

Decode

2.0 tok/s

TTFT

96800 ms

Safe context

Memory

52.0 GB / 20.0 GB

Offload

60%

Memory breakdown

Weights43.9 GB

KV Cache4.9 GB

Runtime1.2 GB

Headroom2.0 GB

See how fast it feels

With memory offload — actual speed may be lower

See how fast it feelsQwen 2.5 72B on RTX 4000 Ada 20GB
1st promptCold start — includes initialization
>Solve: If a train travels at 60 mph for 2.5 hours, how far does it go?
Let me work through this step by step.

Given information:
  - Speed = 60 mph (miles per hour)
  - Time  = 2.5 hours

Formula: Distance = Speed x Time

Calculation:
  Distance = 60 mph x 2.5 h
           = 150 miles

The train travels 150 miles.

Double-check: at 60 mph the train covers 60 miles each hour. In half an hour it covers 30 miles. So in 2.5 hours: 60 + 60 + 30 = 150 miles. Confirmed.
2nd promptWarm — model ready, no init overhead
>What if the train stops for 20 minutes halfway?
The stop doesn't change the total distance covered while moving, but it affects total trip time.

Breakdown:
  - First half: 1.25 hours at 60 mph = 75 miles
  - Stop: 20 minutes (no distance)
  - Second half: 1.25 hours at 60 mph = 75 miles

Total distance: 150 miles (same)
Total time: 2.5 h + 0.33 h = 2.83 hours
Average speed: 150 / 2.83 = 53 mph

The distance stays the same but average speed drops to 53 mph because of the stop.
Estimated: 2.0 tok/s decode · 96.8s TTFT (warm) · 5 tok/s prefill

What limits this setup

Usable VRAM is the main blocker for this model.

Not enough usable memory

The model needs 52.0 GB, but this setup only exposes 20.0 GB of usable VRAM.

Best improvement path

Add more VRAM headroom

The first useful upgrade is more dedicated VRAM so you can fit the model without shrinking context or dropping to a much lower quant.

Performance by workload

Workload	Grade	Fit	Decode	TTFT	Context
Chat	F	Too heavy	2.0 tok/s	52800 ms	4K
Coding	F	Too heavy	2.0 tok/s	96800 ms	4K
Agentic Coding	F	Too heavy	2.0 tok/s	140800 ms	4K
Reasoning	F	Too heavy	2.0 tok/s	114400 ms	4K
RAG	F	Too heavy	2.0 tok/s	176000 ms	4K

Quantization options

How Qwen 2.5 72B (72B params) fits at each quantization level on RTX 4000 Ada 20GB (20.0 GB usable).

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	28.1 GB	Low	F0
Q3_K_S	3	35.3 GB	Low	F0
NVFP4	4

Upgrade options

Hardware that runs Qwen 2.5 72B well

RTX A6000 48GBBest value

48 GB VRAM (+28)768 GB/s (+408)

Makes the model fit on the accelerator instead of staying completely out of reach.8.2 tok/s decode

Makes the model fit on the accelerator instead of staying completely out of reach.

Raises estimated decode speed by about 310%.

~$4,650 MSRP

RTX PRO 5000 Blackwell 48GBNVIDIA upgrade

48 GB VRAM (+28)1344 GB/s (+984)

Makes the model fit on the accelerator instead of staying completely out of reach.16.3 tok/s decode

Makes the model fit on the accelerator instead of staying completely out of reach.

Raises estimated decode speed by about 715%.

~$4,999 MSRP

NVIDIA A16 64GBBudget pick

64 GB VRAM (+44)600 GB/s (+240)

Makes the model fit on the accelerator instead of staying completely out of reach.11.6 tok/s decode

Makes the model fit on the accelerator instead of staying completely out of reach.

Removes host-memory offload, which is usually the single biggest latency and throughput win.

~$6,500 MSRP

NVIDIA H100 80GBBiggest leap

80 GB VRAM (+60)3350 GB/s (+2990)

Makes the model fit on the accelerator instead of staying completely out of reach.69.7 tok/s decode

Makes the model fit on the accelerator instead of staying completely out of reach.

Removes host-memory offload, which is usually the single biggest latency and throughput win.

~$40,000 MSRP

Frequently asked questions

Can RTX 4000 Ada 20GB run Qwen 2.5 72B?

No, Qwen 2.5 72B requires more memory than RTX 4000 Ada 20GB provides.

How much VRAM does Qwen 2.5 72B need?

Qwen 2.5 72B (72B parameters) requires approximately 52.0 GB of memory with Q4_K_M quantization.

What is the best quantization for Qwen 2.5 72B?

The recommended quantization for Qwen 2.5 72B is Q4_K_M, which balances quality and memory efficiency.

What speed will Qwen 2.5 72B run at on RTX 4000 Ada 20GB?

On RTX 4000 Ada 20GB, Qwen 2.5 72B achieves approximately 2.0 tokens per second decode speed with a time-to-first-token of 96800ms using Q4_K_M quantization.

Can RTX 4000 Ada 20GB run Qwen 2.5 72B for coding?

For coding workloads, Qwen 2.5 72B on RTX 4000 Ada 20GB receives a F grade with 2.0 tok/s and 4K context.

What context window can Qwen 2.5 72B use on RTX 4000 Ada 20GB?

On RTX 4000 Ada 20GB, Qwen 2.5 72B can safely use up to 4K tokens of context. The model's official context limit is 131K, but available memory constrains the safe maximum.

What should I upgrade first if Qwen 2.5 72B feels slow on RTX 4000 Ada 20GB?

Add more VRAM headroom. The first useful upgrade is more dedicated VRAM so you can fit the model without shrinking context or dropping to a much lower quant.

See all results for RTX 4000 Ada 20GB See all hardware for Qwen 2.5 72B

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