Although there were no changes in the PlayStation 3 operating system interface or the functionality of the console, the internal components and physical characteristics separate a first and second generation PS3. The first generation is known as the "original" PS3, with its bulky design and smaller internal hard drive. The second generation is known as the "slim" PS3 model, with a smaller weight and size, but larger internal hard drive.
Measure the dimensions of your PlayStation 3 model. If your PS3 measures 32.5 cm in length, 9.8 cm in width and 27.4 cm in height, you have the first generation of PS3. The second generation "slim" PS3 model has dimensions of 29 cm in length, 6.5 cm in width and 29 cm in height.
Find how much memory space is included in the PS3 internal hard drive. The first generation PS3 includes an 80GB hard drive, while the second generation models include an internal hard drive of 120GB and 160GB.
Weigh your PS3 console on a scale to determine the generation. Since the second generation PS3 is more slim, it is also lighter in weight. The first generation PS3 weighs exactly 5 kg while the second generation PS3 weighs 3.2 kg.