Jeff Geerling Puts On the X-Ray Specs to See What Makes a Raspberry Pi 5 Tick Beneath the Surface

YouTuber Jeff Geerling has peered deep into the inner workings of the Raspberry Pi 5 single-board computer — quite literally, by putting one under in an X-ray machine and seeing what lies beneath the surface.

"Following up on my X-ray scans of the Raspberry Pi Zero 2 W two years ago, I had the opportunity to scan the Raspberry Pi 5, working with an electronics inspection lab," Geerling explains. "The board layout has some radical departures from the earlier Pi 4 — besides the Ethernet port and PoE [Power over Ethernet] pins swapping sides back to a Pi 3 and earlier arrangement, the majority of the middle of the board is dominated by expanded IO: five total PCIe lanes, LPDDR4x memory channels, and HDMI signals all routed through the SoC [System-on-Chip]."

Announced back in September and launched in November, the Raspberry Pi 5 is — as you'd expect from the latest in the company's line of popular single-board computers — the fastest Raspberry Pi yet. As well as new central and graphics processors, though, the device has undergone a major change in design — moving "low speed" connectivity to an in-house chip dubbed the RP1 and adding a user-accessible PCI Express lane to a flat flexible circuit (FFC) cable connector at one side of the board.

"The [SoC] package is much smaller than the total package dimension, and you can just make out some of the bonding wires," Geerling says of his X-ray imagery. "I counted all the package solder balls so you don't have to—there are 586 pins coming off the BCM2712 (in a 25×25 BGA [Ball Grid Array], with some pads empty). Those pins route signals to and from all parts of the Pi, but besides the dual 4K60-capable HDMI ports, a lot of that signaling goes through the 4 PCI Express lanes attached to the RP1 chip."

"Those lanes form a little '8-lane highway' on the surface of the Pi's PCB,"
Geerling continues, "with each differential pair holding a tiny set of capacitor 'cars' at one point or another along the route, making the highway analogy complete. The RP1 itself is less than a quarter the size of the full package, with 265 total pins in its BGA, laid out in an 18×18 grid."

Geerling's full write-up with more imagery is available on his website, while even more shots can be found in his video embedded above and on his YouTube channel.