The article investigates why Nvidia L40S and RTX A6000 GPUs show less memory via nvidia‑smi than their advertised 48 GB, revealing that enabled ECC memory reserves a few gigabytes, and demonstrates the effect by toggling ECC on a Tesla‑T4 card.
This article compares NVIDIA's high‑end AI GPUs—H100, A100, and the newer L40S—detailing their specifications, performance trade‑offs, pricing, availability, and suitability for training and inference workloads, while highlighting why L40S can be a cost‑effective alternative for many enterprises.
The NVIDIA L40S GPU, built on the Ada Lovelace architecture with 48 GB GDDR6 memory and 846 GB/s bandwidth, delivers over 1.45 PFLOPS tensor performance and superior FP16/FP32 efficiency for generative AI training and inference, while its lower power and GDDR6 design may influence demand for mid‑range optical modules in data centers.
