You can for example use a controller memory buffer with NVMe and just access the data over mapped PCIe, or you get it to DMA into L3 cache and use/overwrite it

You can for example use a controller memory buffer with NVMe and just access the data over mapped PCIe, or you get it to DMA into L3 cache and use/overwrite it before it gets it's turn at the write-back part of the DRAM memory controller.