A computing device comprises a main memory, an input-output (IO) device, and an input-output memory management unit (IOMMU). The IOMMU may receive an upstream IO write request to the main memory from the IO device, and bypass caching the write request if the write request is within a first memory region of the main memory associated with a non-volatile memory. The IOMMU may cache the write request if the write request is within a second memory region of the main memory associated with a volatile memory.