The DGX Spark 64GB maintains a memory bandwidth of 273 GB/s by utilizing lower-capacity LPDDR5x memory modules rather than reducing the total number of modules.

From the articleNVIDIA Announces DGX Spark 64GB: A 1-PetaFLOP Grace Blackwell Desktop for Local AI Agents, Fine-Tuning, and InferenceAlso in Nvidia debuts $4,999 DGX Spark with half the RAM and storage, amid memory crunch