Advanced Deep Learning Interview Questions, issue 21, Apr 11, 2026
The VRAM Shortcut Trap
Senior Computer Vision Engineer interview at Google DeepMind, and the interviewer asks:
“We are passing high-resolution medical images through a deep, 50-layer CNN. To save VRAM on our H100 GPUs, a junior proposes dropping zero-padding on all convolutions, arguing we only lose a tiny 2-pixel border per layer. Do you approve this PR?”
Don’t say: “Yes, it’s a smart micro-optimization. Valid convolutions skip the zero-computation, saving memory bandwidth and FLOPs. A tiny edge crop on a 4K scan is statistically insignificant to the final classification.”
Trying to save memory by altering convolution semantics breaks the model’s spatial contract instead of addressing the true activation bottleneck.
The full answer, with the mechanism and the arithmetic, is for paid subscribers on Substack.