Same size, different layout
As you can see, while the Raspberry Pi 4 Model B, on the left, is the same size as the Raspberry Pi 3 Model B+, it has a different layout.
The change has been necessary to incorporate the dual micro-HMDI ports on the board.
The new layout means side panels in cases for older Pi boards won't fit correctly. I also found the board overheated when playing video while using an older case, with the computer throttling performance to reduce temperature.
Nick Heath is chief reporter for TechRepublic. He writes about the technology that IT decision makers need to know about, and the latest happenings in the European tech scene.