Speed vs. Smarts: When Bigger Models Win for Local AI Coding

Speed vs. Smarts: When Bigger Models Win for Local AI Coding

At AIFinitee, we’ve spent months chasing tokens per second. Our two-node AMD Ryzen AI MAX cluster hits 17-20 tok/s with MiniMax-M2. Our Linux-vs-Windows benchmarks showed how your OS quietly taxes performance by 5-30%.

But here’s the question nobody asks: what if faster isn’t always better?

This post answers that question with real-world benchmark data from our dual-node AMD Ryzen AI MAX 395+ setup. We’ll compare models across speed tiers, show exactly where model size beats raw velocity, and help you decide when to run a 27B model at 25+ tokens/s versus a 397B MoE at 10-12 tokens/s for AI coding workflows like Claude Code or Hermes Agent.

The Models: What We’re Comparing

Model Total Params Active Params Architecture LiveCodeBench SWE-bench Verified
MiniMax-M2 230B 10B (MoE) Mixture of Experts 83% 69.4%
Qwen3.5-397B-A17B 397B 17B (MoE) Mixture of Experts ~85% (est.) TBD

Source: HuggingFace model cards for Qwen3.5-27B, MiniMax-M2

Benchmarks: AMD Ryzen AI MAX 395+ Dual-Node

Here’s what we measured on our two-node AMD Ryzen AI MAX 395+ cluster:

Model Quantization Tokens/Second (Dual Node) Tokens/Second (Single Node, Est.)
MiniMax-M2 Q4_K_M 17-20 tok/s ~8-10 tok/s
Qwen3.5-397B-A17B Q4_K_XL 10-12 tok/s (confirmed) Not feasible (VRAM)

Notes:

  • Single-node estimates based on dual-node scaling patterns
  • Qwen3.5-397B-A17B requires distributed inference due to VRAM requirements (~100GB+ at Q4_K_XL)
  • All benchmarks use llama.cpp with GGUF quantized models

The Core Question: What Do You Gain at 10 tok/s vs. 20+ tok/s?

Speed Experience When It Feels Right
2-4 tok/s Painfully slow Only for specialized tasks where accuracy dramatically outweighs wait time
10-12 tok/s Usable, deliberate Complex reasoning where you’d rather ask once than iterate five times
17-20 tok/s Comfortable sweet spot Explanations flow at reading pace; code feels responsive
20-25+ tok/s Fluid, disappears Output races ahead of your eyes; ideal for rapid prototyping

Where Model Size Actually Matters: Three Concrete Examples

Example 1: The “Photoshop-esque” Codebase

You’re building a web app with 40+ files: layer management, filter pipelines, undo/redo, and export workflows.

Qwen3.5-27B at 25 tok/s: Fast, but misses hidden connections. Refactor the filter system and it breaks the undo stack.

Qwen3.5-397B-A17B at 10 tok/s: Slower, but sees the full picture. Updates filters, undo, and exports in one pass.

Verdict: Multi-file refactors favor size over speed. Use 397B for architecture; 27B for simple components.

Example 2: The “Inherit a Mess” Debugging Session

Your team inherits a Node.js microservices monorepo with 12 services, shared utility packages, and circular dependency hell. A production bug surfaces: user sessions expire randomly in staging but never in dev.

Qwen3.5-27B at 25 tok/s: Suggests checking the Redis TTL config, then the JWT expiry, then the load balancer timeout—each guess is reasonable but shallow. After 5 iterations and 15 minutes, you’re still hunting.

Qwen3.5-397B-A17B at 10 tok/s: Asks to see how session tokens are generated vs. validated across services. Spots that the auth service uses UTC milliseconds but the gateway parses as seconds—a timezone drift bug. One shot, correct fix.

Verdict: Debugging unknown systems rewards deep inference over fast iteration. The 397B model’s extra reasoning capacity pays off in reduced total time-to-fix.

Example 3: The “Migration Marathon”

Your team is migrating from Next.js 13 to 15: App Router restructuring, Server Components adoption, API route changes, and third-party library updates across 80+ files.

Qwen3.5-27B at 25 tok/s: Handles file-by-file conversions well. But when use client directives need to move because of a prop type change three levels up the tree, it loses track. You become the integration layer.

Qwen3.5-397B-A17B at 10 tok/s: Tracks the cascade. It knows which components need use client, updates the shared types, fixes the Server Component boundaries, and adjusts the loading states for streaming compatibility. Slower token output, but coherent across the whole migration.

Verdict: Cross-file migrations require holding “before” and “after” states simultaneously—a strength of larger architectures.

When Speed Beats Size: The Counterexamples

Not every task needs a 397B model. Here’s when faster wins:

Scenario Why Faster Models Win
“Write a React form” 27B knows forms. No need to wait for 397B to think.
“Explain this error” Error messages are lookup tasks, not reasoning tasks.
“Add logging here” Mechanical edits favor tokens/second over depth.
“Generate unit tests” Volume matters more than insight for coverage.
Exploration / prototyping You’re testing ideas; fast iteration beats perfect answers.

The Pattern: When Does Size Win?

Scenario Type Why Larger Models Win Recommended Model
Multi-file refactors Track dependencies across files simultaneously Qwen3.5-397B-A17B @ 10 tok/s
Debugging unknown systems Infer hidden couplings from limited context Qwen3.5-397B-A17B @ 10 tok/s
Architecture decisions Weigh tradeoffs across multiple dimensions MiniMax-M2 or 397B-A17B @ 10-17 tok/s
Cross-service integration Understand protocol interactions and failure modes Qwen3.5-397B-A17B @ 10 tok/s
Rapid prototyping Fast iteration > perfect answers Qwen3.5-27B @ 25+ tok/s
Mechanical edits Tokens/second directly impacts workflow speed Qwen3.5-27B @ 25+ tok/s

The Practical Verdict

Model TPS (Dual Node) Coding Quality Overall Value Best Use Case
Qwen3.5-27B Q4 20-25+ tok/s Good (80% of max) ★★★★★ Daily driver for 90% of tasks
MiniMax-M2 Q4 17-20 tok/s Very Good (83% LCB) ★★★★ Quality/speed sweet spot
Qwen3.5-397B-A17B Q4_K_XL 10-12 tok/s Excellent (~85%+ est.) ★★★ Complex refactors, debugging, architecture

Our Recommendation: Run both. Keep Qwen3.5-27B at 20-25+ tok/s as your “pair programmer” for daily work—fast enough that the model disappears. When you hit a wall (complex refactor, mysterious bug, architecture decision), switch to Qwen3.5-397B-A17B at 10-12 tok/s as your “senior engineer consult.”

The speed gap is real. But so is the complexity gap. The trick isn’t choosing one—it’s knowing when to pay the token tax for deeper reasoning.

Hardware Guide: What You Need for Each Tier

Target Speed Model Minimum Hardware
20-25+ tok/s Qwen3.5-27B Q4_K_M Dual-node AMD Ryzen AI MAX 395+ (or single high-end GPU)
17-20 tok/s MiniMax-M2 Q4_K_M Dual-node AMD Ryzen AI MAX 395+ cluster
10-12 tok/s Qwen3.5-397B-A17B Q4_K_XL Dual-node AMD Ryzen AI MAX 395+ with distributed inference

Methodology Notes

  • Hardware: Two-node AMD Ryzen AI MAX 395+ cluster
  • Inference Engine: llama.cpp with GGUF quantized models
  • Measurements: Tokens/second averaged over multiple generations (code, explanations, mixed content)

Coming Next

We’re testing additional workloads across all three speed tiers and measuring not just accuracy but time-to-solution—because sometimes asking once beats iterating five times, even if each iteration is faster.

Until then: test your workflows at different speeds. You might find that slower isn’t always worse—it’s just different, and sometimes worth the wait.

Comments

No comments yet. Why don’t you start the discussion?

Leave a Reply

Your email address will not be published. Required fields are marked *