What: NVIDIA's RTX Spark "superchip" (unveiled around Computex / Build 2026) pairs a 20-core Grace CPU with a Blackwell RTX GPU that together address one 128GB unified memory pool over NVLink-C2C — the idea this page explains is unified coherent CPU–GPU memory.
Why: On an ordinary discrete GPU, any data the GPU touches must first be copied from CPU system RAM into GPU VRAM across the PCIe bus — a copy that dominates the moment a model is too big to fit in VRAM. A shared pool lets the GPU read the bytes where they already sit, deleting that copy.
vs prior: A discrete GPU walls its VRAM off behind PCIe and shuttles data both ways with explicit host↔device copies (cudaMemcpy); RTX Spark's coherent unified pool removes the wall, so CPU and GPU see the same physical addresses — no staging copy, no PCIe round-trip.
Think of it as
Two chefs sharing one counter instead of passing plates through a hatch.
