Extreme lag problem.

[Vaeliar]

Hello there, I have a really unfortunate problem. Recently I'm facing extreme lags in KSP.
I will make this clear - everything worked perfectly fine some time ago. It happened yesterday. I hit the lag barrier at JUST 30 parts (Over 30 parts I have around 5-8 fps!). 10 parts works super smooth, so it's not a GPU problem. 40/50 parts begin to stutter like 700 or more parts earlier. What is going on? Tried to uninstall all mods and reinstall the game, but nothing helped me.

My specs:
CPU: Ryzen 5 1600 @ 3.8 GHz
RAM: 16 GB @ 2933 MHz
GPU: R9 380X

Pretty decent specs, like I said, it worked fine, I could run even 300/400 part projects without any noticeable lag. What the ♥♥♥♥ could happen to me?

[flying diomedea]

To start, thanks for not accusing KSP for the lag. Of course while it worked fine up to few days ago, and now doesn't while KSP hasn't changed, the cause lies somewhere else; however I saw far too many users bashing KSP for all kind of problems that weren't caused by the program.

Having reinstalled KSP clean (without mods) also clears that mods aren't the cause. Well done.
Have now to ask, the lag shows with a new game, or is related to a game that has grown more complex with time?
In the latter case, there could be something wrong in that game (and would require quite some effort to diagnose, perhaps could be tied to Garbage Collection routine in Unity misbehaving and I'd have to show some tools to check that; later in case).
In the former case (lag with new game), I'd start monitoring what your system does (Task Manager in Windows works pretty well for that). BTW, what is your OS? Reason is, other SW in background may be tasking your system resources to the point the application in foreground (KSP) becomes less responsive. E.g., please verify if KSP has enough RAM to work with, or the OS keeps shuffling pages to disk trying to make for a shortage (see how much I/O activity occurs).
Also, please know there are other users experienced something similar to your issue, have a read with this thread as hopefully some solution for your case could be shown (if not yet, in future): https://forum.kerbalspaceprogram.com/index.php?/topic/167629-fps-drops-after-each-consecutive-launch-131/

[rose4100]

I think the problem may be with Steam. I have had other games start to lag for no reasion and this has fixed it. In the steam menu, go to "Settings".
- Click Downloads, Clear Download Cache
- Click Web Browsing, Delete Web Browser Cache and Delete All Browser Cookies.

Unfortunately, my KSP isn't lagging so I can't say for sure this will fix the problem, but it has for other games that i own. I hope it helps.

[flying diomedea]

Originally posted by rose4100:

I think the problem may be with Steam. ...

That's an interesting idea. I never launch KSP from Steam, so I'm unable to tell how much it could raise lag. But then is easy to verify, as KSP doesn't need Steam to work: just find the KSP_x64.exe (believe you're using 64bit) within ".../SteamLIbrary/SteamApps/common/Kerbal Space Program" and double click to launch it directly.

[Vaeliar]

Originally posted by flying diomedea:

To start, thanks for not accusing KSP for the lag. Of course while it worked fine up to few days ago, and now doesn't while KSP hasn't changed, the cause lies somewhere else; however I saw far too many users bashing KSP for all kind of problems that weren't caused by the program.

Having reinstalled KSP clean (without mods) also clears that mods aren't the cause. Well done.
Have now to ask, the lag shows with a new game, or is related to a game that has grown more complex with time?
In the latter case, there could be something wrong in that game (and would require quite some effort to diagnose, perhaps could be tied to Garbage Collection routine in Unity misbehaving and I'd have to show some tools to check that; later in case).
In the former case (lag with new game), I'd start monitoring what your system does (Task Manager in Windows works pretty well for that). BTW, what is your OS? Reason is, other SW in background may be tasking your system resources to the point the application in foreground (KSP) becomes less responsive. E.g., please verify if KSP has enough RAM to work with, or the OS keeps shuffling pages to disk trying to make for a shortage (see how much I/O activity occurs).
Also, please know there are other users experienced something similar to your issue, have a read with this thread as hopefully some solution for your case could be shown (if not yet, in future): https://forum.kerbalspaceprogram.com/index.php?/topic/167629-fps-drops-after-each-consecutive-launch-131/

Thank you for you response!

It happens on a new game too. Nothing suspicious on task manager, CPU on 35% max (6/12 so it's normal), GPU on 10-20%. KSP is using tremendous amount of RAM, something like 6/7 GB, so I guess it's enough. I have the newest Windows 10.

I will do some further investigations about this problem, I will update if I find something.

[Vaeliar]

Originally posted by flying diomedea:

Originally posted by rose4100:

I think the problem may be with Steam. ...

That's an interesting idea. I never launch KSP from Steam, so I'm unable to tell how much it could raise lag. But then is easy to verify, as KSP doesn't need Steam to work: just find the KSP_x64.exe (believe you're using 64bit) within ".../SteamLIbrary/SteamApps/common/Kerbal Space Program" and double click to launch it directly.

I will check this too!

[Chibbity]

Do you have a lot of mods?

Could be a conflict throwing a nullerrorexception; that'll tank your FPS fast.

Open up the debug menu with Alt+F12 while in flight experiencing the lag and go to the console, look for a bunch of spamming red text lines.

[flying diomedea]

Originally posted by SocketByte:

It happens on a new game too. Nothing suspicious on task manager, CPU on 35% max (6/12 so it's normal), GPU on 10-20%. KSP is using tremendous amount of RAM, something like 6/7 GB, so I guess it's enough. I have the newest Windows 10.

While the CPU/GPU activity with KSP are more intrinsic with a specific system performance (e.g. with a brand new game, my 1.3.1 KSP makes CPU at 12% and GPU at 37%), the amount of RAM in use seems way off. Just loaded, KSP 1.3.1 takes ~ 1.7 GB RAM (working set, the virtual size is somewhat higher) to raise to ~2.0 GB upon entering Space Center the first time. It would then increase, building crafts, changing scenes, and performing flights. But to arrive at 6-7 GB would take quite some time. Could you check those amounts as I reported (Task Manager does fine)? It would seem as if KSP was loading much more stuff than it should if otherwise (but where from, if mods were removed?)

[Flavourfish 100]

check your game cache.