Qwen3.5 122B-A10B on DCU K100-AI 64GB (海光深算) (64GB) — VRAM, KV Cache & Throughput

Qwen3.5 122B-A10B (122B total, 10B active, Hybrid Linear/Mamba + MoE) uses 69.19 GiB of 4-bit weights (Q4_K_M), requiring 70.03 GiB total at 8K context and 70.59 GiB at 32K on DCU K100-AI 64GB (海光深算) (~51.6 tok/s decode).

Interactive Sizing Workbench

Full Compatibility Report →
64 GB · 1638 GB/s
Exceeds Available GPU Memory
Config-derived formula HF config.json ↗
Memory Allocation Breakdown (GiB) 70.03 GiB (75.19 GB) / 64 GiB (109%)
Model Weights: 69.19 GiB KV Cache & State: 0.28 GiB Runtime & Activation Buffers: 0.56 GiB System RAM Offload: 0 GiB
Required GPU Memory
70.03 GiB
75.19 GB (decimal)
Usable Hardware Memory
60.8 GiB
64 GB (physical)
Safe Headroom
-9.23 GiB
109% utilization
Est. Decode Throughput
~51.6 tok/s
10B active params
Est. Prefill Throughput
~6370 tok/s
4K Prompt TTFT: ~643 ms
Est. Cost / 1M Tokens
$2.38
Hybrid Linear/Mamba + MoE · Apache-2.0

Recommended Hardware for Current Configuration

Best Single GPU
RTX PRO 6000 Blackwell (96GB)
~$8,500
Best Value / Used GPU
2x A100 80GB SXM
160GB · ~$24,000
Apple Unified Memory
Ryzen AI Max+ 395 128GB
~$1,999
Cloud From
Vast.ai · $0.44 / hr
1x A100 80GB SXM

Production Launch Commands

llama.cpp (GGUF)
llama-server -hf unsloth/Qwen3.5-122B-A10B-GGUF:Q4_K_M \
  --ctx-size 8192 -ngl 999 --flash-attn
vLLM
vllm serve Qwen/Qwen3.5-122B-A10B \
  --max-model-len 8192 --gpu-memory-utilization 0.92
Live Token Speed Simulator (TTFT ~643ms · ~51.6 tok/s)
[Qwen3.5 122B-A10B · 70.03 GiB] allocated on target GPU. Prefill completed in TTFT window; streaming autoregressive tokens at memory-bandwidth-bound rate...

Cloud GPU Comparison & Rent-vs-Buy TCO

Verified public rates across RunPod, Vast.ai, Vultr, and DigitalOcean.

Verified: 2026-11-04
Purchase break-even
~64.4 months
Est. local power: $12.77 / mo
Provider Recommended Instance Total VRAM Hourly Rate Monthly at Selected Hours Billing Mode Deploy
RunPod 1x A100 80GB SXM (Community Cloud · PCIe) 80 GB $1.19 / hr $144.70 / mo Per-second Deploy GPU ↗
Vast.ai 1x A100 80GB SXM (Verified Host · SXM4) 80 GB $0.44 / hr $53.75 / mo Spot / On-demand Deploy GPU ↗
Vultr ($300 Free Credit*) 1x A100 80GB SXM (Dedicated Instance · $300 Credit*) 80 GB $2.40 / hr $291.48 / mo Hourly Deploy GPU ↗
Vultr Cloud GPU 1x A100 80GB SXM (Dedicated Instance) 80 GB $2.40 / hr $291.48 / mo Hourly Deploy GPU ↗
DigitalOcean 1x Instinct MI300X 192GB (Dedicated Instance) 192 GB $2.59 / hr $314.94 / mo Per-second Deploy GPU ↗

Rates reflect public listings on the verification date and fluctuate with regional inventory.

Fine-Tuning VRAM Requirements (QLoRA / LoRA / Full) — Qwen3.5 122B-A10B

QLoRA (4b) Exceeds Available GPU Memory
71.63 GiB
Model Weights: 69.19 GiB · Gradients + Optimizer: 1.4 GiB · Act: 1.04 GiB
Recommended GPU: RTX PRO 6000 Blackwell (96GB)
LoRA (16b) Exceeds Available GPU Memory
230.83 GiB
Model Weights: 227.24 GiB · Gradients + Optimizer: 2.2 GiB · Act: 1.39 GiB
Recommended GPU: Instinct MI325X 256GB (256GB)
Full BF16 Exceeds Available GPU Memory
934.12 GiB
Model Weights: 227.24 GiB · Gradients + Optimizer: 704.44 GiB · Act: 2.44 GiB
Recommended GPU: 8x H200 141GB SXM (1128GB)

Engineering Sizing Notes & Optimization Playbook

Quick Hardware Verdict

A single DCU K100-AI 64GB (海光深算) (64GB) cannot hold 4-bit Qwen3.5 122B-A10B (70.03 GiB at 8K) entirely in VRAM. Use multi-GPU tensor parallelism, offload layers to system RAM, or deploy on a larger cloud GPU.

KV Cache & Runtime Tuning

Qwen3.5 122B-A10B uses Hybrid Linear/Mamba + MoE (122B total, 10B active per token). Moving from 8K to 32K context expands FP16 KV cache from 0.28 GiB to 0.84 GiB; enabling 8-bit KV cache (llama.cpp -ctk q8_0 -ctv q8_0 or vLLM --kv-cache-dtype fp8) saves 0.38 GiB at 32K (reducing total VRAM to 70.21 GiB).

VRAM Scaling Across Context Windows (4K to 128K, 4-bit Weights)

Qwen3.5 122B-A10B VRAM scaling from 4K to 128K context (4K: 69.92 GiB, 8K: 70.03 GiB, 32K: 70.59 GiB, 128K: 72.84 GiB) 4K 69.92 GiB (KV 0.18 GiB) 8K 70.03 GiB (KV 0.28 GiB) 32K 70.59 GiB (KV 0.84 GiB) 128K 72.84 GiB (KV 3.09 GiB) DCU K100-AI 64GB (海光深算) (64GB)
Model weights remain constant while attention KV cache grows with context length and batch size.

Quantization Precision & Memory Matrix — Qwen3.5 122B-A10B @ 8K

Quantization Format Weights (GiB) KV Cache Total VRAM (GiB) Decode Speed Compatibility (DCU K100-AI 64GB (海光深算)) Recommended GPU Data Source
Native Weights (BF16 / FP8 / MXFP4 — Lossless) (BF16) 227.24 GiB 0.28 GiB 228.08 GiB (244.9 GB) ~3.6 tok/s Exceeds Available GPU Memory Instinct MI325X 256GB (256GB) Official checkpoint size
FP8 / GGUF Q8_0 (8-bit — Near-Lossless) (Q8_0) 120.72 GiB 0.28 GiB 121.56 GiB (130.52 GB) ~9.5 tok/s Exceeds Available GPU Memory Instinct MI300X 192GB (192GB) Config-derived formula
GGUF Q6_K (6-bit — High Precision) (Q6_K) 93.17 GiB 0.28 GiB 94.01 GiB (100.94 GB) ~16.7 tok/s Exceeds Available GPU Memory Instinct MI300X 192GB (192GB) Config-derived formula
GGUF Q5_K_M (5-bit — Balanced) (Q5_K_M) 80.97 GiB 0.28 GiB 81.81 GiB (87.84 GB) ~25.3 tok/s Exceeds Available GPU Memory RTX PRO 6000 Blackwell (96GB) Config-derived formula
Q4_K_M / UD-Q4_K_XL / AWQ (4-bit — Recommended) (Q4_K_M) 69.19 GiB 0.28 GiB 70.03 GiB (75.19 GB) ~51.6 tok/s Exceeds Available GPU Memory RTX PRO 6000 Blackwell (96GB) Config-derived formula
GGUF IQ4_XS (4.25-bit — Compact) (IQ4_XS) 60.58 GiB 0.28 GiB 61.42 GiB (65.95 GB) ~116.9 tok/s Tight Fit (<8% Headroom) RTX PRO 6000 Blackwell (96GB) Config-derived formula
GGUF Q3_K_M (3-bit — Low VRAM) (Q3_K_M) 55.73 GiB 0.28 GiB 56.57 GiB (60.74 GB) ~124.1 tok/s Fits with Safe Headroom RTX PRO 6000 Blackwell (96GB) Config-derived formula
GGUF UD-Q2_K_XL (2-bit — Extreme MoE) (UD-Q2_K_XL) 39.37 GiB 0.28 GiB 40.21 GiB (43.18 GB) ~157.2 tok/s Fits with Safe Headroom A40 48GB (48GB) Config-derived formula

Technical Specifications & FAQ

Does Qwen3.5 122B-A10B fit on DCU K100-AI 64GB (海光深算) (64GB)?

In 4-bit (Q4_K_M) at 8,192 context, Qwen3.5 122B-A10B requires 70.03 GiB total GPU memory (69.19 GiB weights + 0.28 GiB KV cache + 0.56 GiB runtime buffers) against 60.8 GiB usable on DCU K100-AI 64GB (海光深算), delivering ~51.6 tok/s decode.

How much VRAM does Qwen3.5 122B-A10B need at 32K context?

At 32,768 context tokens, Qwen3.5 122B-A10B (Hybrid Linear/Mamba + MoE) allocates 0.84 GiB for KV cache and state, bringing total 4-bit VRAM to 70.59 GiB (75.8 GB decimal).

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