KSP1 with about 170 mods and 32 gb of DDR5 RAM just showed a major slow up on my i9-13900KF Desktop PC

[rnyboy]

Yesterday I added two additional mods that resulted in a drastic increase in app and craft load times and a lot of stuttering during play until KSP would lock up.  I really don't want to mention the mods by name because I don't think they were at fault but seemed to be the "straw that broke the camel's back" in that before the two new mods were added I could get to the start screen in about 7 minutes and have about 5 gb of my 32 gb  of RAM initially still left free and could work in KSP for something like six or so hours with very little stuttering until getting into the mid to upper 90% of RAM used and then things start to quickly bog down and I  either quit and restarted or eventually get the "Unexpected Stack Overflow" error warning from Unity Analytics.  When KSP is not running the system plus other processes uses around 27% of the available RAM.

After installing those two new mods, one with a fair number of new parts and the other with increased animation effects, the load times went to about 10 minutes and about 98% of memory was being used right at the start screen.  Loading up a craft would take a few minutes when it used to take maybe 30s up to 45s on a bad day.  During the craft loading free memory would often be jumping into the few hundred mb numbers when before it would pretty much stay in the low gbs at worse.   When in flight mode there was 98+% of total RAM used with quite a bit of stuttering and after about 15 or so minutes KSP would lock up.

This morning, I uninstalled the two new apps and things went back to normal.  The memory usage stays around 85% while in flight with no stuttering and smooth graphics with the physics time scale in the green.  So, I'm thinking I may bite the bullet and upgrade from 32gb of RAM to 64gb considering what I've seen suggests I'm bumping up against a lack of free RAM ceiling.   Just wondering if this RAM upgrade sounds about right based on the above recent observations or if there is a better solution that doesn't involve reducing the number of mods.

Edited July 5, 2024 by rnyboy

[Phoenix-D]

Try the Memgraph mod if you haven't already. It improves garbage collection somewhat which can reduce memory usage.

You could also try lowering texture quality. Also try installing those two mods alone and see if they cause the same issue.

[HebaruSan]

4 hours ago, rnyboy said:

two new mods, one with a fair number of new parts

Every part that you add takes up more RAM and adds time to the game's startup.

[rnyboy]

Memgraph sounds interesting.  I'll have to try that.  Thanks.

(Edit:  I looked up MemGraph and linuxgurugamer pointed to another mod called HeapPadder.  It appears to be something like a MemGraph-lite.  I think I'll give that a try first.

2nd edit to the 1st edit...   Looks like MemGraph is a dependency of HeapPadder in that CKAN installed both.

3rd Edit:  After installing MemGraph, and using it for ~30 minutes, I realized this won't solve the issue at the moment.  The real issue seems to be bumping up too close to my max available 32gb of RAM and adding to the heap reduces that small headroom even further.   My install of KSP1 is using up around 25gb of RAM at the start, so not small.   I think I'm going to bite the bullet and double my RAM to 64 gb and then reinvestigate MemGraph because I think that should reduce whatever stutters I do get to a lower number over time. )

I really don't want to lower the texture quality because I like the looks and generally get good fps.  I have an ~650 part ship (Habtech ISS with a docked Benjee10 Space Shuttle) in orbit and the physics slows from 1s in ksp time being equal to1s in real time to 1s ksp being less than 2s in real time.  I can live with that.  Shortly after liftoff from an alphamense launchpad a ~150 part BDB Apollo Saturn V shows around 30 fps the couple of times I've checked and once in orbit I get about 40 fps.

I'm still kind of leaning to upgrade the RAM to 64gb too.  I like to post process astronomy images and sometimes videos and generally the more RAM the better for that as well.

I only upgraded from KSP v1.11.2 to 1.12.5 about two weeks ago because all the mods I was using finally had 1.12+ versions.  I'm now in the process of trying to get orbiting craft, landers, rovers, and bases back to the way I like it.  Like usual, after a major upgrade, many of my v1.11.2 craft files have missing or invalid parts and I need to redo the important ones. 

Edited July 6, 2024 by rnyboy
Just found HeapPadder...

[rnyboy]

Thought I'd finish this topic with the results after upgrading to 64gb.  I'm now running between 175 and 180 mods including MemGraph.  The padheap.cfg is fixed at 16384 (probably could lower it actually) with "visible = true" and "applyPadding = true" in the settings.cfg .  The total memory used was 82% with KSP using about 28 gb of memory when the image below was saved.  I've seen as high as 87% memory used, so between 10% and 15% of total RAM is still free.  I'm sure I could have quite a bit less free because that's a lot of free RAM for Windows and the other apps running in the background.

To test the new 64gb setup I've played with quite a few craft using as few as 96 parts to over 250 from launch to final orbit.   I also have an over 650 part Hab Tech2 ISS with US and Russian parts plus a Dragon-2 cargo ship docked to it in a 100km orbit around Kerbin and so far time between stutters is pretty much always longer than a minute and often more than two minutes.  The stutter time for a garbage-clean is under a second and is typically not even noticed unless I happen to be doing something at the time.

At the moment KSP is behaving very nicely after the new RAM upgrade.  I haven't had a single hiccup or crash due to a memory overflow after playing for many hours straight. 

Edit:  I meant to add that the total loading time is long, about 7 minutes, but that's a onetime thing per playing session.

Edit #2:  I just loaded up KSP1 and went to the VAB.  Shortly after that I looked and % Memory was 88% and Ram used was 47gb.  That's a new observed high but it typically drops down to around 80% after a while of playing and very slowly increases with time played.

The following image gives the frame-rate and memgraph data while the Artemis Construction Kit's ICPS and Orion is in Kerbin orbit...

Edited July 12, 2024 by rnyboy
Added load time.