Note 19

The Model 75 was an outgrowth of IBM’s continuing engineering development effort to enhance the capabilities of the original System/360 offerings. Its main memory operated at 750 nanoseconds and was available in three sizes up to 1,048,576 characters of information. The memory was interleaved up to four ways to obtain increased performance.

Source IBM :

https://www.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP2075.html