How much RAM is enough RAM?

[maddog59]

I've noticed that the system seems to slow down particularly when I'm approaching some of my stations in orbit with lots of parts and ships and such connected.  

I'm running KSP on an HP Pavilion 17 gaming laptop with 16GB of RAM, i7 cpu @ 2.6GHz, and NVIDIA GeForce GTX 1660 GPU (I'm not very technical, I just see this from the Task Manager's Performance window) - Windows 10, obviously.  All is well, generally speaking, but the RAM is maxing out at between 93% and 97% while I'm playing. Everything else seems to be running at reasonable levels, so I've been thinking about increasing the RAM to 32 or 64 GB. 

Will that make much of a difference in the smoothness of the game play when I'm dealing with my larger structures?

 

 

[AHHans]

19 minutes ago, maddog59 said:

Will that make much of a difference in the smoothness of the game play when I'm dealing with my larger structures?

Probably not. (But I'm not 100% sure.)

I play KSP on a Linux machine with also 16GB RAM. And my impression was that KSP likes to allocate lots of RAM^(*), but doesn't really use much of it at any time. I.e. even with a large craft in the physics bubble the machine isn't swapping, but it is the CPU that is the bottleneck. My guess is that your "CPU" isn't at 100% because KSP uses only about 1.5(**) cores of your CPU and the other cores are idle.

P.S. (*) It may be that this isn't really allocated RAM that is actually swapped out, but memory mapped files.
(**) My guess is that only one core is used for the physics simulation, i.e. the big CPU hog of KSP,  and tasks around updating the display etc. can happen in another thread (=core).

[jimmymcgoochie]

KSP is limited by CPU more than anything. The reason the game slows down with high part count vessels inside physics range is because it needs to calculate the interactions of all those hundreds of parts, every frame, and it does so using one single processor thread because that's how the physics engine works. Most modern CPUs have multiple cores to allow lots of stuff to happen at the same time, but KSP can't use those other cores.

Adding parts mods, especially those with detailed interiors or high-definition textures, will increase your RAM use considerably, as do planet packs (I think); adding more RAM will give you more room to add more mods, but it won't make the game run any faster if you're flying with a multi-hundred part vessel nearby.