The Fine-Tuning VRAM Breakdown Calculator & DeepSpeed ZeRO Scaling Matrix provides the exact mathematical formulas required to budget GPU cluster memory and prevent runtime CUDA Out-Of-Memory crashes; total training memory decomposes into 5 components:
Mtotal=Mweights+Mgradients+Moptimizer+Mactivations+Mtemp; for full-parameter AdamW mixed-precision fine-tuning (parameter count
Φ): model weights require
2Φ bytes (FP16), gradients
2Φ bytes, and AdamW optimizer states require
12Φ bytes (FP32 master weights
4Φ + momentum
4Φ + variance
4Φ), totaling a staggering
$16\Phi$ bytes of static memory alone (70B model requires 1,120GB static VRAM); DeepSpeed ZeRO stages partition optimizer states (ZeRO-1), gradients (ZeRO-2), and parameters (ZeRO-3), slashing per-GPU memory to
N16Φ bytes alongside Activation Checkpointing.