This PSRAM chip can add 8 Megabytes of RAM for use on Teensy 4.1. The PSRAM chip is meant to be soldered to the smaller pads on the bottom side of Teensy 4.1, underneath the SD card socket, between pins 31-32 and 33-34. Do not use the larger pads. A single PSRAM chip must be soldered to the smaller pads to be detected.
One PSRAM Chip for 8 MB Memory
Two PSRAM Chips for 16 MB Memory
Memory Test Program
After soldering the PSRAM to your Teensy 4.1, run this memory test program to verify the PSRAM memory really is working properly.
Documentation
Click here for the datasheet for this chip