Pipeline parallelism sounds great for multi-GPU training until you realize GPUs are just sitting there waiting between pipeline stages. Most implementations have brutal idle time - one GPU finishes its forward pass and then... nothing. Just burning electricity while waiting for the next stage.

The problem: traditional pipeline parallelism creates these gaps where earlier stages finish but can't start new work because later stages are still processing. It's like having a 8-GPU cluster where only 3-4 are actually working at any given moment.

Ravnest apparently has a different approach to scheduling that keeps GPUs fed with work instead of idling. The key insight: you can overlap computation if you're smart about how you schedule micro-batches across stages.

This matters because if you're training something like a 70B parameter model, those idle cycles add up to real money. A 30-40% utilization improvement means the difference between a $50k training run and a $35k one.