Microsoft has introduced new external storage requirements for Xbox Series X/S. The installed high-speed PCIe 4.0 SSD should significantly reduce loading times and features a capacity of 802GB which will be enough for five 8 big AAA games. But if you need to expand your storage, you will have to use a USB-based storage device or a proprietary high-speed connector.
You can use the high-speed connector to enable plug and play storage upgrades using high-speed NVMe SSDs from Seagate (official manufacturer), but they will be costly. However, if you are a little low on budget, then as per Microsoft’s confirmed requirements, you can use external devices that are USB 3.0 only and have a minimum storage capacity of 128GB.
Currently, Seagate is the official manufacturer of the Microsoft’s proprietary solution, and there’s only one variant of the NVME SSD available. You can preorder it from Bestbuy at a price tag of $219.99. Microsoft has said that it plans to bring more variants(512G B, etc.) and suppliers. You can expect the same performance as the internal SSD because the NVMe SSD by Seagate shares the same format.