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.

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