There are reasons to assume that data retention might drop exponentially as temperature increases. So if you care about the data, you'll want to avoid overheating your storage media.
Power-off storage temperature is a problem for MLC NAND, but when powered on the NAND cells need to reach a high temperature to operate properly. If you are cooling the flash chips with a heatsink (rather than cooling the controller) you will be forcing the device to dump power into the cells to heat them to a temperature where they work properly.
3D NAND hits its best program time and raw bit error rate at about 70C.
3D NAND hits its best program time and raw bit error rate at about 70C.
Edit: See data table on page 27. Retention is directly proportional to device active temperature, i.e. higher cell temperature during programming leads to higher retention. https://www.jedec.org/sites/default/files/Alvin_Cox%20%5bCom...