#+TITLE: PC Engines APU Comparison
#+DATE: 2020-06-17T00:50:06-04:00
#+DRAFT: false
#+DESCRIPTION: Comparison between PC Engines APU machines
#+TAGS[]: hardware pcengines
#+KEYWORDS[]: hardware pcengines
#+SLUG:
#+SUMMARY:

#+ATTR_HTML: :alt PC Engines Comparison
#+ATTR_HTML: :title PC Engines Comparison
[[file:pc%20engines%20vs.png]]

I've been looking at the [[https://www.pcengines.ch/apu2.htm][PC Engines APU]] line for a while. They're a
line of medium size single board PCs with a DB9 serial connector and
no VGA port. They also have gigabit Ethernet. Because of this they're
often used as firewall machines.

I want to get one and use it as either the home router, or an
experimental server to mess around with. Quite a few OpenBSD folks use
them and recommend them as OpenBSD router and server hardware. They
aren't too expensive, have decent specs and a small physical
footprint.

One thing that's always confused me was the naming scheme, which is a
little confusing at first. Initially there was the APU, then the APU2,
as described on their site, which makes sense. Then the APU model
numbers get a little confusing. They come in several variants, I'll
list them here for context.

#+CAPTION: Taken from the PC Engines website
#+BEGIN_SRC
 apu2d0 (2 GB DRAM, 2 i211AT NICs)
 apu2e2 (2 GB DRAM, 3 i211AT NICs)
 apu2e4 (4 GB DRAM, 3 i210AT NICs)
 apu3c2 (2 GB DRAM, 3 i211AT NICs, optimized for 3G/LTE modems)
 apu3c4 (4 GB DRAM, 3 i211AT NICs, optimized for 3G/LTE modems)
 apu4d2 (2 GB DRAM, 4 i211AT NICs)
 apu4d4 (4 GB DRAM, 4 i211AT NICs)
 #+END_SRC

What do the letters between the numbers mean? What is the significance
of the numbers in the first place?

Let's take the =apu3c2= as an example. The =3= here means it's version
3 of the APU board. The APU 1 is no longer sold, so it's left out of
the list on the PC Engines website, along with most of their
re-sellers. The letter =c= is the revision of that board. It's pretty
much irrelevant for comparison. You'll want to get the most recent
one, as listed on the PC Engines website. The revisions are mostly
minor tweaks to the board. The final number, =2=, is the number of gigabytes
of RAM (in most cases).

The APU2E2 boards have a single mSATA slot, and a regular SATA
connector, two mPCIe slots, and a SIM tray. It comes with 2 external
USB 3.0 type A ports, 2 internal USB 2.0 ports (header only), an SD
card slot, and a GPIO header. It also has 3 Intel i211AT gigabit
NICs. Using the SIM tray will remove the ability to use one of the two
mPCIe slots.

So what are the major differences between version numbers? They all
use the same CPU, the quad core AMD Embedded G series GX-412TC running
at 1 GHz. Most other components on the boards are the same as
well. I'll give a description of the differences relative to the APU2
board.

The APU2D0 is the same as the regular APU2, but without a GPIO
headers, and it has only 2 NICs.

The APU3 has an extra SIM tray, and the first slot, which is mSATA
only on the APU2, can be used as either an mSATA or USB 3G/LTE Modem
slot. The second slot can only be used for a modem. It also lets you
do GPIO tray swapping and failover, so you can use only a single modem
for 2 SIMs.

The APU4D2 has 4 NICs instead of 3, and the second slot is modem
only. It has 2 GB of RAM.

The APU4D4 is the same as the APU4D2, except it has dual SIM trays. It
has 4 GB of RAM.

I found a lot of this information wasn't really obvious to upon first
reading the PC Engines website, as there's no direct comparison
between the board, and the site relies on you flipping between pages
to find the details. The re-seller website I looked at also didn't
elaborate on the differences.

| Board  | RAM  | Slot 1      | Slot 2      | Slot 3 | Ethernet Controllers | SIM Slots | USB 2.0 | Headers |
|--------+------+-------------+-------------+--------+----------------------+-----------+---------+---------|
| [[https://www.pcengines.ch/apu2d0.htm][apu2d0]] | 2 GB | mSATA       | mPCIe/Modem | mPCIe  | 2 i211AT             |         1 |       2 | No      |
| [[https://www.pcengines.ch/apu2e2.htm][apu2e2]] | 2 GB | mSATA       | mPCIe/Modem | mPCIe  | 3 i211AT             |         1 |       2 | Yes     |
| [[https://www.pcengines.ch/apu2e4.htm][apu2e4]] | 4 GB | mSATA       | mPCIe/Modem | mPCIe  | 3 i210AT             |         1 |       2 | Yes     |
| [[https://www.pcengines.ch/apu3c2.htm][apu3c2]] | 2 GB | mSATA/Modem | Modem       | mPCIe  | 3 i211AT             |         2 |       4 | Yes     |
| [[https://www.pcengines.ch/apu3c4.htm][apu3c4]] | 4 GB | mSATA/Modem | Modem       | mPCIe  | 3 i211AT             |         2 |       4 | Yes     |
| [[https://www.pcengines.ch/apu4d2.htm][apu4d2]] | 2 GB | mSATA       | Modem       | mPCIe  | 4 i211AT             |         1 |       2 | Yes     |
| [[https://www.pcengines.ch/apu4d4.htm][apu4d4]] | 4 GB | mSATA/Modem | Modem       | mPCIe  | 4 i211AT             |         2 |       2 | Yes     |