The difference in bandwidth between ASUS and Gigabyte graphics cards is probably due to the way in which bandwidth is calculated or specified by each manufacturer. The ASUS TUF Gaming GeForce RTX 4060 Ti card has a memory speed of 18 Gbps on a 128-bit interface, giving a bandwidth of 288 Gbps (18 Gbps * 128 bits / 8 bits per byte). It is possible that Gigabyte is using another method to display the bandwidth or that there is an error in the specification. To clarify, it would be useful to check each manufacturer's official technical specifications.