Nemotron 3 Ultra 550B-A55B on DCU K100-AI 64GB (海光深算) (64GB) — VRAM, KV Cache & Throughput

Nemotron 3 Ultra 550B-A55B (550B total, 55B active, Hybrid Linear/Mamba + MoE) uses 310.97 GiB of 4-bit weights (Q4_K_M), requiring 311.95 GiB total at 8K context and 312.23 GiB at 32K on DCU K100-AI 64GB (海光深算) (~2 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) 311.95 GiB (334.95 GB) / 64 GiB (487%)
Model Weights: 310.97 GiB KV Cache & State: 0.41 GiB Runtime & Activation Buffers: 0.57 GiB System RAM Offload: 0 GiB
Required GPU Memory
311.95 GiB
334.95 GB (decimal)
Usable Hardware Memory
60.8 GiB
64 GB (physical)
Safe Headroom
-251.15 GiB
487% utilization
Est. Decode Throughput
~2 tok/s
55B active params
Est. Prefill Throughput
~1158 tok/s
4K Prompt TTFT: ~3537 ms
Est. Cost / 1M Tokens
$1661.11
Hybrid Linear/Mamba + MoE · NVIDIA Open

Recommended Hardware for Current Configuration

Best Single GPU
Multi-GPU Required
—
Best Value / Used GPU
2x B200 180GB
360GB · ~$80,000
Apple Unified Memory
Mac Studio M3 Ultra 512GB
~$9,500
Cloud From
RunPod · $11.96 / hr
2x B200 180GB

Production Launch Commands

llama.cpp (GGUF)
llama-server -hf nvidia/NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16:Q4_K_M \
  --ctx-size 8192 -ngl 999 --flash-attn
vLLM
vllm serve nvidia/NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16 \
  --max-model-len 8192 --gpu-memory-utilization 0.92
Live Token Speed Simulator (TTFT ~3537ms · ~2 tok/s)
[Nemotron 3 Ultra 550B-A55B · 311.95 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
~6.8 months
Est. local power: $7.45 / mo
Provider Recommended Instance Total VRAM Hourly Rate Monthly at Selected Hours Billing Mode Deploy
RunPod 2x B200 180GB (Community Cloud) 360 GB $11.96 / hr $1454.34 / mo Per-second Deploy GPU ↗
Vast.ai 2x B200 180GB (Verified Host) 360 GB $15.00 / hr $1824.49 / mo Spot / On-demand Deploy GPU ↗
Vultr ($300 Free Credit*) 8x A100 80GB SXM (Dedicated Instance · $300 Credit*) 640 GB $19.18 / hr $2331.80 / mo Hourly Deploy GPU ↗
Vultr Cloud GPU 8x A100 80GB SXM (Dedicated Instance) 640 GB $19.18 / hr $2331.80 / mo Hourly Deploy GPU ↗
DigitalOcean 8x Instinct MI300X 192GB (Dedicated Instance) 1536 GB $20.72 / hr $2519.55 / 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) — Nemotron 3 Ultra 550B-A55B

QLoRA (4b) Exceeds Available GPU Memory
319.87 GiB
Model Weights: 310.97 GiB · Gradients + Optimizer: 7.7 GiB · Act: 1.2 GiB
Recommended GPU: 2x B200 180GB (360GB)
LoRA (16b) Exceeds Available GPU Memory
1038.17 GiB
Model Weights: 1024.45 GiB · Gradients + Optimizer: 12.1 GiB · Act: 1.62 GiB
Recommended GPU: 8x B200 180GB (1440GB)
Full BF16 Exceeds Available GPU Memory
4203.1 GiB
Model Weights: 1024.45 GiB · Gradients + Optimizer: 3175.8 GiB · Act: 2.85 GiB
Recommended GPU: Multi-GPU Required

Engineering Sizing Notes & Optimization Playbook

Quick Hardware Verdict

A single DCU K100-AI 64GB (海光深算) (64GB) cannot hold 4-bit Nemotron 3 Ultra 550B-A55B (311.95 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

Nemotron 3 Ultra 550B-A55B uses Hybrid Linear/Mamba + MoE (550B total, 55B active per token). Moving from 8K to 32K context expands FP16 KV cache from 0.41 GiB to 0.69 GiB; enabling 8-bit KV cache (llama.cpp -ctk q8_0 -ctv q8_0 or vLLM --kv-cache-dtype fp8) saves 0.19 GiB at 32K (reducing total VRAM to 312.04 GiB).

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

Nemotron 3 Ultra 550B-A55B VRAM scaling from 4K to 128K context (4K: 311.89 GiB, 8K: 311.95 GiB, 32K: 312.23 GiB, 128K: 313.35 GiB) 4K 311.89 GiB (KV 0.36 GiB) 8K 311.95 GiB (KV 0.41 GiB) 32K 312.23 GiB (KV 0.69 GiB) 128K 313.35 GiB (KV 1.81 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 — Nemotron 3 Ultra 550B-A55B @ 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) 1024.45 GiB 0.41 GiB 1025.43 GiB (1101.05 GB) ~0.8 tok/s Exceeds Available GPU Memory Multi-GPU Required Official checkpoint size
FP8 / GGUF Q8_0 (8-bit — Near-Lossless) (Q8_0) 544.24 GiB 0.41 GiB 545.22 GiB (585.43 GB) ~1.1 tok/s Exceeds Available GPU Memory Multi-GPU Required Config-derived formula
GGUF Q6_K (6-bit — High Precision) (Q6_K) 420.03 GiB 0.41 GiB 421.01 GiB (452.06 GB) ~1.4 tok/s Exceeds Available GPU Memory Multi-GPU Required Config-derived formula
GGUF Q5_K_M (5-bit — Balanced) (Q5_K_M) 364.54 GiB 0.41 GiB 365.52 GiB (392.47 GB) ~1.7 tok/s Exceeds Available GPU Memory Multi-GPU Required Config-derived formula
Q4_K_M / UD-Q4_K_XL / AWQ (4-bit — Recommended) (Q4_K_M) 310.97 GiB 0.41 GiB 311.95 GiB (334.95 GB) ~2 tok/s Exceeds Available GPU Memory Multi-GPU Required Config-derived formula
GGUF IQ4_XS (4.25-bit — Compact) (IQ4_XS) 272.43 GiB 0.41 GiB 273.41 GiB (293.57 GB) ~2.4 tok/s Exceeds Available GPU Memory Multi-GPU Required Config-derived formula
GGUF Q3_K_M (3-bit — Low VRAM) (Q3_K_M) 250.62 GiB 0.41 GiB 251.6 GiB (270.15 GB) ~2.6 tok/s Exceeds Available GPU Memory Instinct MI355X 288GB (288GB) Config-derived formula
GGUF UD-Q2_K_XL (2-bit — Extreme MoE) (UD-Q2_K_XL) 176.52 GiB 0.41 GiB 177.5 GiB (190.59 GB) ~4.2 tok/s Exceeds Available GPU Memory Instinct MI325X 256GB (256GB) Config-derived formula

Technical Specifications & FAQ

Does Nemotron 3 Ultra 550B-A55B fit on DCU K100-AI 64GB (海光深算) (64GB)?

In 4-bit (Q4_K_M) at 8,192 context, Nemotron 3 Ultra 550B-A55B requires 311.95 GiB total GPU memory (310.97 GiB weights + 0.41 GiB KV cache + 0.57 GiB runtime buffers) against 60.8 GiB usable on DCU K100-AI 64GB (海光深算), delivering ~2 tok/s decode.

How much VRAM does Nemotron 3 Ultra 550B-A55B need at 32K context?

At 32,768 context tokens, Nemotron 3 Ultra 550B-A55B (Hybrid Linear/Mamba + MoE) allocates 0.69 GiB for KV cache and state, bringing total 4-bit VRAM to 312.23 GiB (335.25 GB decimal).

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