Thursday, December 25, 2025

Nvidia + Groq

 

1. The current stack (why it’s constrained)

Components

  • HBM (High Bandwidth Memory)
    • Extremely fast, very close to the GPU
    • Expensive, supply-constrained, thermally dense

  • CoWoS (TSMC advanced packaging)
    • Required to mount HBM next to GPU
    • Bottleneck: cost, yield, capacity

  • CUDA GPU architecture
    • Optimized for training + flexible workloads
    • Inference efficiency is good, but not maximal

Result

✅ Amazing for training
❌ Overkill + expensive for large-scale inference
❌ Memory bandwidth ≠ utilization for token streaming


2. Groq’s LPU philosophy (why it’s different)

Key ideas

  • Deterministic execution
    • No cache misses
    • No dynamic scheduling

  • Compiler-defined dataflow
    • Memory access is planned, not guessed

  • Inference-only focus
    • Tokens flow like packets through a network

What this avoids

  • No HBM requirement

  • No CoWoS dependency

  • No massive cache hierarchies

👉 Performance comes from predictability, not brute force bandwidth


3. Where NVLink fits perfectly

NVLink strengths

  • Ultra-high bandwidth chip-to-chip interconnect

  • Low latency, memory-semantic links

  • Scales across:
    • dies
    • packages
    • boards
    • racks

The key insight

If inference is streaming, memory can be distributed.

Instead of:

[GPU + HBM][GPU + HBM][GPU + HBM]

You get:

[LPU] ⇄ NVLink ⇄ [LPU] ⇄ NVLink ⇄ [LPU]

Each chip:

  • Owns a slice of weights

  • Streams activations forward

  • Never needs full model state locally


4. The “bypass CoWoS + HBM” architecture

Hypothetical combined stack

┌───────────────┐ │ LPU Die │ ← Groq-style deterministic core │ (SRAM-heavy) │ └──────┬────────┘ │ NVLink ┌──────▼────────┐ │ LPU Die │ └──────┬────────┘ │ NVLink ┌──────▼────────┐ │ LPU Die │ └───────────────┘

Why this works

  • Inference = sequential token flow

  • Weights = static

  • NVLink = model-scale fabric

  • SRAM + streaming > HBM + caching

This turns the model into the system, not the chip.


5. Why this makes sense for Nvidia specifically

Nvidia gains

  • Escapes HBM supply + CoWoS bottleneck

  • Adds a pure inference SKU

  • Keeps NVLink as the moat

  • Complements CUDA (training) instead of replacing it

Groq-style IP contributes

  • Compiler-driven scheduling

  • Deterministic latency (huge for real-time AI)

  • Power efficiency at scale

Strategic symmetry

TrainingInference
CUDA GPULPU
HBMDistributed SRAM
CoWoSNVLink fabric
ThroughputLatency + efficiency

6. Bottom line

You’re not wrong to say:

“This actually makes a ton of sense.”

Architecturally:

  • Training wants flexibility + brute force

  • Inference wants determinism + streaming

  • NVLink is already the missing glue

  • HBM is the wrong tool for token pipelines

Great — let’s make this concrete and visual by walking through a step-by-step token flow in an NVLink-connected, Groq-style inference system, and then contrast it with today’s GPU+HBM approach.


1. First: the mental picture (what “streaming inference” really means)

Key property of LLM inference

  • Tokens are generated one at a time

  • Each token:

    1. Passes through every layer

    2. Uses fixed weights

    3. Produces one output vector

This is not a big parallel matrix problem like training.
It’s a pipeline problem.


2. Traditional GPU inference (why HBM is overkill)

What happens today (simplified)

For every token:

  1. Load weights from HBM

  2. Move activations through caches

  3. Synchronize warps

  4. Stall on cache misses

  5. Repeat for next layer

Consequences

  • 🔥 Massive bandwidth use

  • ⏳ Unpredictable latency

  • 💸 Expensive silicon (HBM + CoWoS)

  • 😬 GPU is solving problems inference doesn’t have

GPUs assume:

“You might need anything, anytime.”

Inference reality:

“I know exactly what I need and when.”


3. Groq-style LPU token flow (deterministic pipeline)

Step-by-step (single chip)

  1. Token embedding enters

  2. Layer 1 compute starts immediately

  3. Output streams directly into Layer 2

  4. No cache lookup

  5. No dynamic scheduling

  6. No stalls

Think of it like:

  • An assembly line

  • Not a warehouse with forklifts

Latency becomes:

latency ≈ number_of_layers × fixed_cycle_cost

Predictable. Boring. Fast.


4. Now add NVLink: model-scale pipelining

Split the model across chips

Example: 96-layer model, 6 chips

ChipLayers
LPU 11–16
LPU 217–32
LPU 333–48
LPU 449–64
LPU 565–80
LPU 681–96

Token journey

Token t ↓ [LPU 1] → NVLink → [LPU 2] → NVLink → ... → [LPU 6] ↓ Output token

While:

  • LPU 2 processes token t

  • LPU 1 already processes token t+1

➡️ Full pipeline utilization


5. Why NVLink is the secret weapon

NVLink advantages here

  • Memory-semantic (not packet guessing)

  • Deterministic latency

  • Orders of magnitude faster than PCIe

  • Designed for tight synchronization

This lets Nvidia:

  • Treat multiple chips as one logical inference engine

  • Without HBM coherence nightmares

  • Without giant monolithic dies


6. SRAM + streaming beats HBM + caching (for inference)

Why SRAM is enough

  • Weights are:

    • Static

    • Reused

    • Predictable

  • Access patterns are known at compile time

So:

  • Keep hot weights in SRAM

  • Stream cold weights once

  • Never “hunt” for data

HBM is amazing when:

  • Access is random

  • Working set is huge

  • Compute is chaotic

Inference is none of those.


7. Why this scares everyone (and excites Nvidia)

Hyperscalers

  • Lose differentiation if inference becomes “plug-and-play”

  • GPU margins shrink at scale

Nvidia upside

  • Owns:

    • NVLink

    • Compiler stack

    • Ecosystem

  • Can sell:

    • GPUs for training

    • LPUs for inference

    • One fabric for both

Strategic punchline

Training creates intelligence.
Inference delivers intelligence.
Nvidia already owns the road between them.


8. One-sentence takeaway

Inference wants to be a factory line, not a warehouse — and NVLink turns multiple small, deterministic chips into one massive, perfectly synchronized machine.

If you want next:

  • 🔍 Where this breaks (very large context windows)

  • ⚖️ Comparison vs TPU / Cerebras

  • 🔧 What compiler magic is required

  • 📈 Why latency SLAs change everything

Just tell me which direction to go.

which hyperscalers and what can they do

Here’s a clear, non-hand-wavy map of which hyperscalers are most exposed to an Nvidia-style deterministic inference fabric (GPU for training, LPU-like for inference), why, and what realistic moves they have.


The hyperscalers (ranked by exposure)

1. Google (DeepMind + GCP) — most exposed

Why

  • TPU already is a deterministic, inference-friendly architecture

  • Heavy internal reliance on TPU v4/v5 for cost control

  • NVLink-style external fabric threatens TPU’s differentiation

What Google can do

  • Double down on TPU

    • Push TPU as the inference + training stack

    • Keep it vertically integrated (hardware → compiler → model)

  • ⚠️ Downside:

    • TPU is not an ecosystem

    • Customers want portability, not lock-in

Reality

Google is the only hyperscaler already playing this game — and Nvidia is trying to take it from them.


2. AWS (Amazon) — economically exposed, strategically flexible

Why

  • Largest inference bill by far

  • Massive deployment of Inferentia / Trainium

  • Margins matter more to AWS than prestige silicon

What AWS can do

  • Scale Inferentia hard

    • Improve compiler + model support

    • Compete on price-per-token

  • Play vendors against each other

    • Nvidia for premium

    • Inferentia for volume

  • ❌ Cannot abandon Nvidia entirely (customer demand)

Reality

AWS doesn’t need to win architecturally — it just needs inference to be cheap.


3. Microsoft Azure — strategically trapped

Why

  • OpenAI dependency

  • Public commitment to Nvidia

  • Less internal silicon maturity for inference

What Microsoft can do

  • ⚠️ Incremental custom accelerators

    • Late to the party

  • ⚠️ Lean on Nvidia partnerships

  • ❌ Very hard to pivot without breaking OpenAI alignment

Reality

Microsoft is the most locked-in hyperscaler right now.


4. Meta (Facebook) — dangerous wildcard

Why

  • Massive inference workloads (feeds, ads, assistants)

  • Strong internal hardware teams

  • Open-source models = inference at scale

What Meta can do

  • Design internal LPUs

    • Meta already builds custom inference silicon

  • Optimize models for streaming inference

  • Undercut everyone on cost

  • ❌ Doesn’t sell cloud → no ecosystem leverage

Reality

Meta doesn’t need customers — just efficiency. That makes them dangerous.


5. Apple (honorable mention)

Why

  • Edge inference, not cloud

  • Already uses deterministic accelerators (Neural Engine)

Reality

Apple is proof this architecture works — just not a cloud competitor.


What hyperscalers can actually do (options matrix)

OptionWho can pull it offRisk
Build in-house LPUsGoogle, Meta, AWSCompiler + ecosystem burden
Price war on inferenceAWSMargin compression
Lock customers inGoogleCustomer backlash
Partner deeply with NvidiaMicrosoftVendor dependence
Open inference standardsMeta (maybe)Helps competitors too

Why Nvidia’s move is uniquely threatening

Hyperscalers can build chips.
They cannot easily build ecosystems.

Nvidia already has:

  • NVLink (fabric)

  • CUDA / compiler stack

  • Deployment mindshare

  • Model vendor alignment

If Nvidia adds:

  • Deterministic inference silicon

  • That bypasses HBM and CoWoS

  • While plugging into the same software stack

Then hyperscalers face a brutal choice:

Build everything themselves — or buy a cheaper, better, integrated solution.


The uncomfortable truth for hyperscalers

  • Training is prestige

  • Inference is cost

  • Whoever wins inference wins AI margins

And inference is moving toward:

  • Deterministic

  • Streaming

  • Fabric-scaled

  • Boring (in the best way)

That’s exactly Nvidia’s comfort zone.


One-line takeaway

Hyperscalers can build chips, but Nvidia is building the road system — and inference traffic is about to explode.

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