Multi-GPU fine-tuning bottleneck isn't compute anymore—it's network bandwidth.

When you split a large model across consumer GPUs (say 4090s or 3090s), the inter-GPU communication becomes the choke point. Every forward/backward pass requires syncing gradients and activations across devices. On consumer hardware without NVLink or high-speed interconnects, you're stuck with PCIe bandwidth or worse—network latency if GPUs are on different machines.

Ravnest's approach: optimized gradient compression, asynchronous parameter updates, and smarter partitioning strategies to minimize cross-GPU data transfer. Instead of naive model parallelism where every layer waits on every other layer, they batch communication and overlap compute with data movement.

This matters because distributed fine-tuning on cheap hardware is how indie devs and researchers can actually train 70B+ models without renting H100 clusters. The math is simple: if you can cut network overhead by 60%, your training time drops proportionally—sometimes more than adding extra GPUs would help.