The visualization of mass storage controllers and flash memory chips in the USB2.0, USB3.0 and solid state device (SSD) devices was performed using a thermo-elastic optical indicator microscopy system. Heat distributions corresponding to the various operation/loading parameters such as writing block sizes were analyzed, which was showed device behavior on heating. Direct measurements of the temperature by a thermocouple were implemented in order to investigate the operation thermal states of the devices under test (DUTs) in the idle regime. Heat temperature differences dependence on loading block size (0.25 kB – 64 MB) was found for all DUTs. In order to explain the heat variation dependence on block size a series of measurements of the DUTs transfer rates were performed. The data transfer rate is drastically changed depending on the transferred block size (8 B – 128 MB), (0.2 kB/s – 7 MB/s), (0.3 kB/s – 21 MB/s), (2 kB/s – 92 MB/s) and (3.7 kB/s – 222 MB/s) for USB2.0, USB3.0, HDD, and SSD, respectively.