I have also had performance issues with the C4 on 2.2.3. It was much worse on the earlier builds of 2.2.3 than it is now on the later ones. I was chatting to @gopher.ny about it about a month ago and he offered this:
“ I'll take a closer look at C4 performance once we're done with outright bugs/issues with 2.2.3. In case you're wondering, C4s and earlier hubs run a different version of Linux than C5s and up, and they also run 64-bit JVM vs. 32-bit JVM in C5s+. Trying to come up with settings that would speed up one while at least not harm the other was quite an adventure, and I'm inclined to just have different sets of JVM parameters for different generations of hub at this point.“
