Qwen2.5-VL 72B VRAM: 48GB, 64GB, 80GB, 96GB or 192GB?

Short answer: 48GB is a Q4 file-size trap, 64GB is the practical Q4 tier, 80GB is a Q8 file-size trap, 96GB is the practical Q8 tier, and 192GB is the practical official-BF16 tier. Every GGUF path must include its separate multimodal projector plus cache, vision work and runtime allocations.

Qwen2.5-VL 72B files and practical tiers

Deployment path	Displayed files	Combined file size	Planning tier
ggml-org Q4_K_M + Q8 projector	47.416GB + 0.752GB	48.167GB	48GB cannot hold files; 64GB practical
ggml-org Q4_K_M + F16 projector	47.416GB + 1.410GB	48.826GB	48GB cannot hold files; 64GB practical
ggml-org Q8_0 + Q8 projector	77.263GB + 0.752GB	78.014GB	80GB file-size trap; 96GB practical
ggml-org Q8_0 + F16 projector	77.263GB + 1.410GB	78.673GB	80GB file-size trap; 96GB practical
Official Qwen BF16 safetensors	38 shards totaling 146.822GB	146.822GB	160GB constrained; 192GB practical

Why 48GB and 80GB are traps

The smallest complete displayed Q4 pair is 48.167GB, already greater than a nominal 48GB decimal capacity before loading cache, images or buffers. The Q8 pair is at least 78.014GB; adding the arithmetic 8K FP16/BF16 language cache of 2.5GiB exceeds an 80GB label before vision and runtime allocations. Partial offload may run, but it is not full accelerator residency.

Use 64GB as the practical Q4 starting point and 96GB for Q8. Longer contexts, large/multiple images, video or concurrent requests may require more.

KV cache: 320KiB per allocated text token

Qwen’s official configuration lists 80 language layers, eight KV heads and a 128-element head dimension. With FP16/BF16 keys and values, one sequence uses 2 × 80 × 8 × 128 × 2 = 327,680 bytes, or 320KiB per allocated text token.

Allocated text tokens	FP16/BF16 KV payload
8K	2.5GiB
16K	5GiB
32K	10GiB
64K	20GiB
128K architectural maximum	40GiB

Official BF16: why 160GB remains constrained

The official checkpoint occupies 146.822GB before cache. Adding the arithmetic 8K cache reaches roughly 149.5GB before vision encoding and runtime buffers; 32K reaches roughly 157.6GB before those allocations. A nominal 160GB pool therefore has little usable headroom. Treat it as a constrained target and 192GB as the clearer starting tier.

Large vision workloads add their own pressure

• Dynamic resolution: image dimensions change visual-token count and encoder work.
• Multiple images: image count increases preprocessing and prompt state.
• Video: resolution, sampled frames, duration and frame rate affect memory and compute.
• Projector precision: the Q8_0 and F16 community projectors differ by about 659MB.
• Concurrency: parallel requests multiply cache and intermediate allocations.
• Multi-device placement: aggregate capacity does not erase interconnect, topology, runtime or per-device allocation constraints.

Reproducible Qwen2.5-VL 72B fit test

1. Record repository, revision, every shard/projector file, size and checksum.
2. Record runtime/version and confirm image input works for this exact package.
3. Record model, projector and cache precision plus the per-device placement map.
4. Record interconnect/topology, system RAM and any CPU or disk offload.
5. Fix image dimensions/count, video settings, text allocation, output target and concurrency.
6. Measure each accelerator and system memory before load, after load, after vision encoding and at peak generation.
7. Ask image-grounded questions and record latency, throughput, fallback and errors.

Start with the Qwen2.5-VL family guide, compare the 32B exact guide, the multimodal hub, and the generic 70B sizing guide.

Use the 70B hardware guide, 48GB–96GB capacity guide, multi-GPU guide, VRAM calculator and benchmark submission.

Larger current-generation path: the Qwen3-VL 235B-A22B guide covers exact split-file totals, 188KiB-per-token cache math and multi-device placement.

Sources and limits

• Qwen official 72B repository
• Qwen official configuration
• Qwen2.5-VL release article
• ggml-org community GGUF conversion
• HighVRAM methodology

Reviewed October 25, 2026. Artifact sizes and architecture fields were read from the cited repositories. HighVRAM has not independently benchmarked every runtime, topology, image/video workload or quantization. File size is not peak resident memory.