A data-centre team is sizing GPU nodes for a large language model training job. Which characteristic most directly drives the decision to prioritise aggregate GPU memory capacity over single-GPU latency?
- ALow-latency GPU memory reduces the time-to-first-token metric that training pipelines report to operators.
- BQuantisation to INT8 precision shrinks memory footprint enough that capacity planning becomes irrelevant for training runs.
- CModel weights and optimizer states must all reside in GPU memory simultaneously during the forward and backward passes. Correct
- DThroughput-per-watt efficiency determines whether the cluster can sustain the sustained compute throughput needed for each training step.
Why A is wrong: Time-to-first-token is an inference serving metric and is not a primary training objective; confusing the two is a common mistake when candidates carry inference intuition into training contexts.
Why B is wrong: INT8 quantisation is primarily applied at inference to trade a small accuracy cost for speed and efficiency; mixed-precision training typically uses FP16 or BF16 with FP32 master weights, and capacity pressure remains significant.
Why C is correct: During training, the full model parameters, gradients, and optimizer states must coexist in accelerator memory at once, making total capacity the binding constraint rather than per-request latency.
Why D is wrong: Throughput-per-watt is a key metric when selecting inference hardware to maximise served requests within a power budget; for training, raw compute throughput and memory capacity take priority over energy efficiency ratios.