Hi,
I don't think you have to worry then. You have to understand that some heat is generated by the drive being active, then some heat is generated via transfer from the case and motherboard parts (I/O area) to the drive, because a computer generates heat in the case, motherboard, power supply, drives, video card, and the CPU. These USB drives also do not have any cooling except being out of the case where it is cooler than directly in the case. The most intense heat is generated in the case. Therefore, warmer than normal because of generated and transferred heat. Hope this helps. Have a nice day and enjoy the forum.