What's the difference between APU2 and APU3 boards?

Posted by Natalia Wieczorek on 

APU2 and APU3 boards are very similar in design; In fact APU3 can be seen as a variant of APU2 optimized for LTE. See /knowledge-base/apu-boards-spec-comparison for the full comparison.

The main difference is that APU3 board has two SIM slots, and is optimized for LTE connectivity. It means that you can connect two mPCIe LTE modems and have 2 additional links for failover or as a main connection. Even if you are just planning on having one LTE/3G connection, we recommend APU3 as this board has been extensively tested by PC Engines and optimized for this purpose.

Routing/Networking performance of APU2 and APU3 does not differ in a noticeable way. Both boards handle regular networking very well.

There are two typical uses for APU3 boards:

  • one main connection via cable NIC and a second, failover connection via LTE modem (for critical systems that must always be online)
  • single LTE connection serving as a main gateway. (for remote locations that don't have cable broadband connectivity)

Power usage is minimally higher in case of APU3.

APU3B4 image showing two SIM slots (upper right corner).

APU2C4 image showing one SIM slot.

It's important to note that APU boards don't have built-in LTE/3G modems. Modems must be purchased separately and connected to the mPCIe slots. 

There are several modems that have been tested and are known to work well with APU3. See the list below:

  • Sierra Wireless MC8790
  • Sierra Wireless MC730x
  • Sierra Wireless MC77xx
  • Ericsson f5521 
  • Ericsson f5321gw 
  • HUAWEI ME909u-521