I first noticed it with the Galacticraft furnaces and now I'm seeing it with the compressor as well. Sometimes they run normally and sometimes they run incredibly slowly. For example a compressed steel in the fuel powered compressor just took ~80 seconds to process and the furnace is similarly very slow. It's almost like the server is skipping ticks like crazy in an attempt to keep up. If that's the case then it seems like I would have to spam machines to get a decent processing rate and that's not a good feedback loop as it just adds that much more server load. Vanilla furnaces always seem to run normally. Nuclearcraft furnaces seem to have the same issue.
I do not but I was staring at the progress bar in the machine watching it take the 80 seconds I mentioned above.
If you're not in the same chunk as the machine they take longer as chunks you are not directly in are slowed down to allow for better TPS
The machine was directly across a chunk boundary, moving into that chunk it runs at the speed I expect. Does the ticket based chunkloading keep all the machines in the relevant chunks at full speed?
Yes, iron ones as long as you're online, gold for both online and offline, while gold takes up 3x while offline and 1x when online, so no need to have both iron + gold in the same chunk