Only if there is no collisions and everything can freely phase through everything else.
As you get close probably when both ships bounding boxes overlap your PC has to calculate if any blocks from either ship are touching. The ways you can reduce the lag is have smaller ships or less complicated ships or a better computer. Note your own turrets are also causing collision calculations when they rotate. So less moving rails or turrets also helps. Having the rail controller set to speed zero may help with the lag from stationary rail docked entities, so does having an air gap around them.
Note your graphics card does not help with the collision calculations only your computers processor. There are a lot of games that don't use the processor much but use the graphics card a lot. A lot of gaming computers focus more on the high end graphics card and not the processor which can be a problem. Starmade and other block building games with physics is one of the few game types that can really stress your processor once your ships/creations are big enough.
So your FPS drop could be because even through your graphics card keeps up generating the pictures the processor can't compute all the physics involved. That's in single player mode. In multiplayer mode whoever is running the server, I assume needs the good processor to handle all the physics calculations but I could be wrong. I also assume the lag in the physics calculations will then have knock on effects into the other issues your experiencing.
As it is from what I have read starmade also uses multiple threads/cores for some physics calculations. Like missile explosions. So during combat atleast, starmade is using multiple cores on your computers processor to help share the calculation load and not using only a single core/thread like a lot of other computer games.
i guess an xeon e3 eight core 3.7ghz cpu with some highend nvidia graphics card and 32G ram ought to be enough.
this is a typical starmade syndrome -- getting a fairly technical justification why basic stuff is not working like it's somehow 'understandable'.
it never worked from the beginning, at least not, since i started playing. is something going to change, that supposedly make this work? or is this just one of those many 'glitches' we have to accept as one of the fundamental truth about this game?
Well without something a little more specific I'll have a bit of difficulty helping.
I just got a 940k block ship with 16 turrets and docked that to an identical ship and then docked the combined ship to a 10mil+ block station with 40+ turrets and rail door etc.. without any noticeable lag in single player. I was using the pickup rail touching the docking rail so i hit the station a couple times before docking still without lag. My computer is intel i7 3.3Ghz 6 core, NVidia GTX980 and 64GB of memory which is comparable to your system. The extra memory is limited by the limit set for starmade. Since the maximum memory I've ever used in starmade is around the 6GB mark there shouldn't be any difference between have 8GB to any amount of memory.
So I can only think of a few things that might be causing issues for you.
1. Number of collision calculations. One is you have a lot of turrets/rail docked stuff grouped close together which multiplies collision lag badly when you get close to something else. The number of docked entities for collision calculations gets for worse for each extra one. Area triggers also causes a lot of lag as it has to check if anything is in the same area as each area trigger block. So I don't use area triggers for large scale hanger doors.
2. Memory Limits. There is enough stuff in game to use more than the memory limit allocated to starmade/java. I don't think you can run starmade on the 32bit java so I'll assume everyone is on 64bit java. My max memory setting for starmade is 16gb and I think the max I've used is around 6GB. I'm not sure what the default setting is for a fresh install. So you might want to check this setting if you haven't already.
3. Less likely but possible. Update java to the latest version. There here is the catch the starmade launcher loses the java install location every time you update java as the install folder changes. So you have to tell the launcher where the new version is.
4. Is this docking to a planet? The size of some of the planet plates get so large I imagine there might be a lot more collision calculations involved.
If its not any of the above then its starting to get tricky and probably beyond me atleast without further information.
Someday maybe. I've been playing since 2011 and its always been this way - In fact it has gotten worse instead of better - around the time the new rail system came out it's always a lag fest - with just two ships. Wish there was a way to turn off bumping I think that would drastically improve performance.