DeepSeek V3.2 (685B) on Ryzen AI Max+ 395 128GB (128GB) — 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 Ryzen AI Max+ 395 128GB (~3.1 tok/s decode).

Interactive Sizing Workbench

Full Compatibility Report →
128 GB · 256 GB/s
Exceeds Available GPU Memory
Measured GGUF shard size HF config.json ↗
Memory Allocation Breakdown (GiB) 378.79 GiB (406.72 GB) / 128 GiB (296%)
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
99.8 GiB
128 GB (physical)
Safe Headroom
-278.99 GiB
296% utilization
Est. Decode Throughput
~3.1 tok/s
37B active params
Est. Prefill Throughput
~335 tok/s
4K Prompt TTFT: ~12232 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 ~12232ms · ~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
~1.2 months
Est. local power: $2.55 / 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 Ryzen AI Max+ 395 128GB (128GB) 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) Ryzen AI Max+ 395 128GB (128GB)
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 (Ryzen AI Max+ 395 128GB) 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) ~2.6 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) ~4.2 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) ~6 tok/s Exceeds Available GPU Memory Instinct MI325X 256GB (256GB) Measured GGUF shard size

Technical Specifications & FAQ

Does DeepSeek V3.2 (685B) fit on Ryzen AI Max+ 395 128GB (128GB)?

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 99.8 GiB usable on Ryzen AI Max+ 395 128GB, 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).

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