DeepSeek V3.2 (685B) on H800 80GB SXM (80GB) — VRAM, KV Cache & Throughput

DeepSeek V3.2 (685B) (685.36B total, 37B active, Multi-head Latent Attention (MLA) MoE) uses 377.56 GiB of 4-bit weights (Q4_K_M), requiring 378.79 GiB total at 8K context and 380.75 GiB at 32K on H800 80GB SXM (~3.1 tok/s decode).

Interactive Sizing Workbench

Full Compatibility Report →
80 GB · 3350 GB/s
Exceeds Available GPU Memory
Measured GGUF shard size HF config.json ↗
Memory Allocation Breakdown (GiB) 378.79 GiB (406.72 GB) / 80 GiB (473%)
Model Weights: 377.56 GiB KV Cache & State: 0.66 GiB Runtime & Activation Buffers: 0.57 GiB System RAM Offload: 0 GiB
Required GPU Memory
378.79 GiB
406.72 GB (decimal)
Usable Hardware Memory
76 GiB
80 GB (physical)
Safe Headroom
-302.79 GiB
473% utilization
Est. Decode Throughput
~3.1 tok/s
37B active params
Est. Prefill Throughput
~6950 tok/s
4K Prompt TTFT: ~589 ms
Est. Cost / 1M Tokens
$316.85
Multi-head Latent Attention (MLA) MoE · MIT

Recommended Hardware for Current Configuration

Best Single GPU
Multi-GPU Required
—
Best Value / Used GPU
4x H200 141GB SXM
564GB · ~$128,000
Apple Unified Memory
Mac Studio M3 Ultra 512GB
~$9,500
Cloud From
Vast.ai · $3.54 / hr
8x A100 80GB SXM

Production Launch Commands

llama.cpp (GGUF)
llama-server -hf unsloth/DeepSeek-V3.2-GGUF:Q4_K_M \
  --ctx-size 8192 -ngl 999 --flash-attn
vLLM
vllm serve deepseek-ai/DeepSeek-V3.2 \
  --max-model-len 8192 --gpu-memory-utilization 0.92
Live Token Speed Simulator (TTFT ~589ms · ~3.1 tok/s)
[DeepSeek V3.2 (685B) · 378.79 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
~13.2 months
Est. local power: $14.9 / mo
Provider Recommended Instance Total VRAM Hourly Rate Monthly at Selected Hours Billing Mode Deploy
RunPod 2x B300 288GB Blackwell Ultra (Community Cloud) 576 GB $13.88 / hr $1687.81 / mo Per-second Deploy GPU ↗
Vast.ai 8x A100 80GB SXM (Verified Host · SXM4) 640 GB $3.54 / hr $429.98 / 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) — DeepSeek V3.2 (685B)

QLoRA (4b) Exceeds Available GPU Memory
383.91 GiB
Model Weights: 377.56 GiB · Gradients + Optimizer: 5.18 GiB · Act: 1.17 GiB
Recommended GPU: 4x H200 141GB SXM (564GB)
LoRA (16b) Exceeds Available GPU Memory
1259.8 GiB
Model Weights: 1250.09 GiB · Gradients + Optimizer: 8.14 GiB · Act: 1.57 GiB
Recommended GPU: 8x B200 180GB (1440GB)
Full BF16 Exceeds Available GPU Memory
5128.14 GiB
Model Weights: 1250.09 GiB · Gradients + Optimizer: 3875.28 GiB · Act: 2.77 GiB
Recommended GPU: Multi-GPU Required

Engineering Sizing Notes & Optimization Playbook

Quick Hardware Verdict

A single H800 80GB SXM (80GB) cannot hold 4-bit DeepSeek V3.2 (685B) (378.79 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

DeepSeek V3.2 (685B) uses Multi-head Latent Attention (MLA) MoE (685.36B total, 37B active per token). Moving from 8K to 32K context expands FP16 KV cache from 0.66 GiB to 2.62 GiB; enabling 8-bit KV cache (llama.cpp -ctk q8_0 -ctv q8_0 or vLLM --kv-cache-dtype fp8) saves 1.31 GiB at 32K (reducing total VRAM to 379.44 GiB).

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

DeepSeek V3.2 (685B) VRAM scaling from 4K to 128K context (4K: 378.45 GiB, 8K: 378.79 GiB, 32K: 380.75 GiB, 128K: 388.61 GiB) 4K 378.45 GiB (KV 0.33 GiB) 8K 378.79 GiB (KV 0.66 GiB) 32K 380.75 GiB (KV 2.62 GiB) 128K 388.61 GiB (KV 10.48 GiB) H800 80GB SXM (80GB)
Model weights remain constant while attention KV cache grows with context length and batch size.

Quantization Precision & Memory Matrix — DeepSeek V3.2 (685B) @ 8K

Quantization Format Weights (GiB) KV Cache Total VRAM (GiB) Decode Speed Compatibility (H800 80GB SXM) Recommended GPU Data Source
Native Weights (BF16 / FP8 / MXFP4 — Lossless) (FP8) 1250.09 GiB 0.66 GiB 1251.32 GiB (1343.59 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) 664.3 GiB 0.66 GiB 665.53 GiB (714.61 GB) ~1.6 tok/s Exceeds Available GPU Memory Multi-GPU Required Measured GGUF shard size
GGUF Q6_K (6-bit — High Precision) (Q6_K) 513.45 GiB 0.66 GiB 514.68 GiB (552.63 GB) ~2.1 tok/s Exceeds Available GPU Memory Multi-GPU Required Measured GGUF shard size
GGUF Q5_K_M (5-bit — Balanced) (Q5_K_M) 443.46 GiB 0.66 GiB 444.69 GiB (477.48 GB) ~2.5 tok/s Exceeds Available GPU Memory Multi-GPU Required Measured GGUF shard size
Q4_K_M / UD-Q4_K_XL / AWQ (4-bit — Recommended) (Q4_K_M) 377.56 GiB 0.66 GiB 378.79 GiB (406.72 GB) ~3.1 tok/s Exceeds Available GPU Memory Multi-GPU Required Measured GGUF shard size
GGUF IQ4_XS (4.25-bit — Compact) (IQ4_XS) 333.74 GiB 0.66 GiB 334.97 GiB (359.67 GB) ~3.6 tok/s Exceeds Available GPU Memory Multi-GPU Required Measured GGUF shard size
GGUF Q3_K_M (3-bit — Low VRAM) (Q3_K_M) 298.24 GiB 0.66 GiB 299.47 GiB (321.55 GB) ~4.1 tok/s Exceeds Available GPU Memory Multi-GPU Required Measured GGUF shard size
GGUF UD-Q2_K_XL (2-bit — Extreme MoE) (UD-Q2_K_XL) 229.67 GiB 0.66 GiB 230.9 GiB (247.93 GB) ~5.9 tok/s Exceeds Available GPU Memory Instinct MI325X 256GB (256GB) Measured GGUF shard size

Technical Specifications & FAQ

Does DeepSeek V3.2 (685B) fit on H800 80GB SXM (80GB)?

In 4-bit (Q4_K_M) at 8,192 context, DeepSeek V3.2 (685B) requires 378.79 GiB total GPU memory (377.56 GiB weights + 0.66 GiB KV cache + 0.57 GiB runtime buffers) against 76 GiB usable on H800 80GB SXM, delivering ~3.1 tok/s decode.

How much VRAM does DeepSeek V3.2 (685B) need at 32K context?

At 32,768 context tokens, DeepSeek V3.2 (685B) (Multi-head Latent Attention (MLA) MoE) allocates 2.62 GiB for KV cache and state, bringing total 4-bit VRAM to 380.75 GiB (408.83 GB decimal).

Evaluate This Model on Other GPUs

Evaluate Other Models on This Hardware