XSX will come with 1TB that is half as fast as the PS5 ssd. Both have an upgrade slot. Microsoft is requiring XSX owners to buy very specific nvme drives to be able to use XSX tier games, they are rumored to be $220 for 1 TB. Meanwhile Sony isnt requiring that which means the PS5 price is $100 per TB. XSX owners can still use standard nvme, but it will downgrade the games on that ssd to X1X tier.