The modern NVMe SSDs have a multi-queue architecture to increase overall performance, where a submission queue can serve a stream from the host. Because of the asymmetry of read/write latency in NAND flash memory, the modern NVMe SSDs usually use the write buffer and the write mapping cache in DRAM space to extend the lifetime and reduce writes in NAND flash memory. In the paper, we will propose a multi-stream-aware DRAM allocation strategy inside solid-state drives (SSDs). The proposed strategy is to predict the suitable DRAM space for the write buffer and the write mapping cache of each stream to reduce writes in NAND flash memory under a fixed DRAM size or variable DRAM space. According to the experimental results, the proposed strategy can predict a suitable DRAM space for each stream to effectively reduce writes in NAND flash memory in a multi-stream SSD.