The ASRock Q2900M is a microATX motherboard that comes with a Pentium J2900 “Bay Trail-D” quad-core CPU soldered on it. It has one USB 3.0 and two SATA-300 ports, but its highlights are actually its low power consumption and low cost.
The Pentium J2900 is an SoC (System on a Chip), meaning it has the CPU, GPU, memory controller, and chipset in the same chip. Even with all these components, the chip dissipates only 10 W. Despite its name, the Pentium J2900 is an Atom CPU targeted to desktop computers. It runs at 2.41 GHz (2.66 GHz boost clock) and has 2 MiB of L2 memory cache.
The Bay Trail-D family also has other quad-core (Celeron J1850 and J1900, and Pentium J2850) and dual-core (Celeron J1750 and J1800) models, all of them with a TDP of only 10 W, so you can find similar motherboards based on those other processors too.
You can see the ASRock Q2900M motherboard in Figure 1. It uses the microATX form factor, measuring 8.9” x 7.2” (226 x 183 mm).