GPU × use-case guide · Reasoning / agentic

Is the L40 a good GPU for reasoning / agentic?

The L40 is a ada NVIDIA GPU with 48 GB GDDR6 (864 GB/s), 362 TFLOPS BF16 / 733 TFLOPS FP8, and a 300 W TDP. Reasoning / agentic workloads care most about long output generations (chain-of-thought), so decode throughput and KV-cache headroom dominate. Here's how the L40 measures up.

What models fit on a single L40?

Weights only, reserving ~25% of the 48 GB for KV cache, activations and fragmentation. ✓ = fits on one card.

Largest single-card fit: Qwen 2.5 14B at BF16, Gemma 2 27B at FP8, Qwen 2.5 72B at INT4. Bigger models need tensor-parallel across 8 cards.

L40 for reasoning / agentic, specifically

Reasoning / agentic is context-heavy, so the KV cache — not the weights — is what fills the 48 GB. On the L40 you'll trade context length against batch size: long prompts mean fewer concurrent requests. Because it's latency-sensitive, run it at low batch sizes on a fast framework (vLLM ≈ 85% MFU) rather than maximising batch. Size it precisely on the calculator.

L40 pricing across providers

Verdict

At 48 GB, the L40 is a solid mid-to-high-tier choice for reasoning / agentic: single-card up to Qwen 2.5 14B (BF16) or Gemma 2 27B (FP8), and cost-effective at ~$0.99/hr.