More than 20 million Raspberry Pi boards have been sold so far, and their popularity shows no signs of slowing down. This ebook rounds up the details and specs for the latest board, the $25 Raspberry Pi 3 Model A+.

From the ebook:

What is the Raspberry Pi 3 Model A+?
The Raspberry Pi 3 Model A+ is a $25 single-board computer that is basically a cheaper, smaller, and slightly stripped-back version of the Raspberry Pi 3 B+. It’s an update to the existing $20 Raspberry Pi 1 Model A+, which was released in 2014 and is based on the same hardware as the first Raspberry Pi that came out in 2012.

How is the Raspberry Pi 3 Model A+ different from the Raspberry Pi 1 Model A+?
Compared with the old board, the Pi 3 Model A+ is based on much newer and faster hardware, some 10 times faster, according to some CPU benchmarks.

The Pi 3 A+ runs on a system-on-chip that has a quad-core 1.4GHz CPU—the same found in the Pi 3 B+—compared with the older single-core 700MHz processor in the first-gen A+ board.

The biggest leap forward is the addition of 802.11ac Wi-Fi to the Pi 3 A+, making it far easier to get started and get data on and off the board than was the case with the original A+, which had no network connectivity—neither Ethernet nor Wi-Fi.

The downside is the new Model A+ costs $5 more, $25 against the first board’s $20 price tag. It also consumes a good deal more power, with benchmarking by Gareth Halfacree for official Raspberry Pi publication The MagPi Magazine finding it consumes 1.13W when idle and 4.1W under load. This is in contrast to earlier benchmarks that suggest a Pi 1 A+ with a USB Wi-Fi dongle consumes around 0.8W when idle.

How is the Raspberry Pi 3 Model A+ different from the Raspberry Pi 3 Model B+?
The Pi 3 A+ costs $10 less than B+, and as you’d expect, certain features have been cut to reduce the price.

The A+ has 512MB RAM, half the memory of the B+; it has only a single USB 2.0 port, compared with four on the B+; and there’s no Ethernet.

It’s also smaller, a squat square size (65mm × 56.5mm) compared with the rectangular (85.6mm × 56.5mm) Model B+. The dimensions of the new A+ are the same as the first-gen A+.

The A+’s power consumption is lower, with Halfacree’s benchmarking finding the Pi 3 A+ had a 1.13W power draw when idle and 4.1W draw when under load, compared with 2.3W when idle and 5.7W under load for the B+.

Operating temperatures appear to be slightly lower on the Pi 3 A+ as well, with Halfacree measuring 60.8°C on the A+ and 62.5C on the B+ (141.4°F and 144.5°F) after 10 minutes of CPU load.