

Batch size: FSDP alone enables slightly higher batch sizes compared to DDP. Using FSDP + AC enables ~3x batch size compared to DDP for the 350M param model and ~5.5x for 900M param model. Even for 10B, a max batch size of ~20 which is fairly decent. This essentially enables larger global batch size using fewer GPUs which is especially useful for contrastive learning tasks.





  Figure 2: Max local batchsize possible for different configurations

Conclusion