Can Qwen 3.5 35B A3B run on RX 6800 XT 16GB?

Q: What should I upgrade first if Qwen 3.5 35B A3B feels slow on RX 6800 XT 16GB?

Remove offload with more accelerator memory. Prioritize a GPU or unified-memory tier that fits the whole model natively. Removing offload usually helps more than small compute gains.

YES — With Q2_K

A82Great

Estimated from fit model

Qwen 3.5 35B A3B needs ~17.6 GB VRAM. RX 6800 XT 16GB has 16.0 GB. With Q2_K quantization, expect ~32 tok/s.

Runtime: llama.cppCapacity: OffloadBandwidth: MediumStack: StandardBottleneck: Host offload

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.

Qwen 3.5 35B A3B at Q4_K_M needs 25.3 GB — too much for RX 6800 XT 16GB (16.0 GB). Runs at Q2_K (17.6 GB) with low quality.

Capabilities:

Select quantization to explore

Q4_K_M (Medium quality) — 25.3 GB, exceeds 16.0 GB available

25.3 GB required16.0 GB available

158% VRAM needed

9.3 GB over capacity — needs offload or smaller quantization

Fit status

Too heavy

Decode

11.3 tok/s

TTFT

17112 ms

Safe context

Memory

25.3 GB / 16.0 GB

Offload

40%

Memory breakdown

Weights21.3 GB

KV Cache1.5 GB

Runtime0.9 GB

Headroom1.6 GB

See how fast it feels

With memory offload — actual speed may be lower

See how fast it feelsQwen 3.5 35B A3B on RX 6800 XT 16GB
1st promptCold start — includes initialization
>Write a Python function to sort a list
Here's a Python function that sorts a list using quicksort:

def quicksort(arr):
    if len(arr) <= 1:
        return arr
    pivot = arr[len(arr) // 2]
    left   = [x for x in arr if x < pivot]
    middle = [x for x in arr if x == pivot]
    right  = [x for x in arr if x > pivot]
    return quicksort(left) + middle + quicksort(right)

# Example usage
numbers = [3, 6, 8, 10, 1, 2, 1]
print(quicksort(numbers))  # [1, 1, 2, 3, 6, 8, 10]

The algorithm picks a pivot, partitions the list into smaller, equal, and larger elements, then recursively sorts each partition and concatenates the results.
2nd promptWarm — model ready, no init overhead
>Now add type hints and a docstring
def quicksort(arr: list[int]) -> list[int]:
    """Sort a list using the quicksort algorithm.

    Args:
        arr: List of integers to sort.

    Returns:
        A new sorted list.
    """
    if len(arr) <= 1:
        return arr
    pivot = arr[len(arr) // 2]
    left   = [x for x in arr if x < pivot]
    middle = [x for x in arr if x == pivot]
    right  = [x for x in arr if x > pivot]
    return quicksort(left) + middle + quicksort(right)

Added type hints for the input and return type, plus a Google-style docstring.
Estimated: 11.3 tok/s decode · 17.1s TTFT (warm) · 28 tok/s prefill

What limits this setup

It fits through host-memory offload, and offload is the main reason performance drops.

CPU or host-memory offload is active

About 10% of the working set spills out of accelerator memory, which usually hurts latency and sustained decode throughput.

Very little memory headroom

You can run the model, but there is not much room left for longer context, bigger batches, extra apps, or future model updates.

Best improvement path

Remove offload with more accelerator memory

Prioritize a GPU or unified-memory tier that fits the whole model natively. Removing offload usually helps more than small compute gains.

Buy headroom, not only minimum fit

A slightly larger memory tier gives you safer context growth and makes the recommendation more future-proof.

Increase host RAM if you keep offloading

This setup may need roughly 1.3 GB of extra host RAM just for the offloaded portion, before OS and other tools.

Performance by workload

Workload	Grade	Fit	Decode	TTFT	Context
Chat	F	Too heavy	12.0 tok/s	8775 ms	4K
Coding	F	Too heavy	11.3 tok/s	17112 ms	4K
Agentic Coding	F	Too heavy	10.1 tok/s	28020 ms	4K
Reasoning	F	Too heavy	11.3 tok/s	20224 ms	4K
RAG	F	Too heavy	10.1 tok/s	35024 ms	4K

Quantization options

How Qwen 3.5 35B A3B (35B params) fits at each quantization level on RX 6800 XT 16GB (16.0 GB usable).

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	13.7 GB	Low	F0
Q3_K_S	3	17.2 GB	Low	F0
NVFP4	4

Get started

Copy-paste commands to run Qwen 3.5 35B A3B on your machine.

Run

ollama run qwen3.5:35b-a3b

Upgrade options

Hardware that runs Qwen 3.5 35B A3B well

RX 7900 XTX 24GBBest value

24 GB VRAM (+8)960 GB/s (+448)

Makes the model fit on the accelerator instead of staying completely out of reach.60 tok/s decode

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

Raises estimated decode speed by about 431%.

~$999 MSRP

Radeon AI PRO R9700 32GBBudget pick

32 GB VRAM (+16)640 GB/s (+128)

Makes the model fit on the accelerator instead of staying completely out of reach.52.2 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.

~$1,899 MSRP

Radeon Pro W6800 32GBAMD upgrade

32 GB VRAM (+16)

Makes the model fit on the accelerator instead of staying completely out of reach.39.6 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.

~$2,249 MSRP

Frequently asked questions

Can RX 6800 XT 16GB run Qwen 3.5 35B A3B?

Yes, RX 6800 XT 16GB can run Qwen 3.5 35B A3B at Q2_K quantization (Very compromised (needs ~1.3 GB host RAM)). The recommended Q4_K_M requires 25.3 GB which exceeds available memory, but at Q2_K it needs only 17.6 GB. Expected decode speed: 32.3 tok/s.

How much VRAM does Qwen 3.5 35B A3B need?

Qwen 3.5 35B A3B (35B parameters) requires approximately 25.3 GB at Q4_K_M quantization. On RX 6800 XT 16GB, it fits at Q2_K using 17.6 GB.

What is the best quantization for Qwen 3.5 35B A3B?

The recommended quantization is Q4_K_M, but on RX 6800 XT 16GB the best fitting quantization is Q2_K, which uses 17.6 GB.

What speed will Qwen 3.5 35B A3B run at on RX 6800 XT 16GB?

On RX 6800 XT 16GB, Qwen 3.5 35B A3B achieves approximately 32.3 tokens per second decode speed with a time-to-first-token of 5999ms using Q2_K quantization.

Can RX 6800 XT 16GB run Qwen 3.5 35B A3B for coding?

For coding workloads, Qwen 3.5 35B A3B on RX 6800 XT 16GB receives a F grade with 11.3 tok/s and 4K context.

What context window can Qwen 3.5 35B A3B use on RX 6800 XT 16GB?

On RX 6800 XT 16GB, Qwen 3.5 35B A3B can safely use up to 4K tokens of context at Q2_K quantization. The model's official context limit is 131K, but available memory constrains the safe maximum.

See all results for RX 6800 XT 16GB See all hardware for Qwen 3.5 35B A3B

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