S3xySteak

Thx for your answer. Hopefully TFP will be able to solve this problem in the future.

So sad I will shut down those @%$# running in the background and try again. Afterburner can be used to overclock GPU. Besides, it can monitor almost everything. For examples, GPU stuff, CPU temperature, CPU usage of each thread, CPU clock of each thread, CPU power, RAM usage, FPS, Frame time, average fps, 1%Low fps. You can check it in settings. It is very useful and convenient. Strangely, MSI do not make any tips to make user know those function.

I assembled and maintained this pc myself and I think it was not thermal throttling. I monitor my pc by MSI afterburner and it shows that the GPU and CPU works well. I noticed that it said 15g RAM was used. I checked my windows task manager and it said 7dtd.exe has used 10g RAM. Is 10g RAM enough? Maybe I should upload a video on Youtube to show the problem exactly in a few days.

With the number of zombies increases , GPU usage was reduced from around 98% to around 65% with low FPS. It is always happened in a level-5 mission house. After I kill all zombies in level-5 mission house , the FPS and GPU usage becomes normal. Meanwhile, some people in TIE BA( like reddit in China) said maybe the zombies' pathfinding AI cause the low FPS, because FPS is not reduced too much(compared with that in level-5 mission house) in horde night. The difference between level-5 mission house and horde night is that the horde night usually do not have the complex terrain. I have used some mod to boost the FPS like "Simple FPS Saver" "Weed reduction" "Yakov's A20 Performance Mod" , but it has no visible effect. 5600x-flck2000 gtx1070 8g*2RAM-4000c16 WDC-sn500

Version A20.6 stable My pc has 16g RAM The save is from my 14 days of survival play, the map is the default 8K map When I set the Virtual Memory 1g to 8g .This game crushes when it was loading my save. I tried again and my pc shut down :( When I set the virtual memory 1g to 16g. I can play this game without errors So this game takes about 16G to 32G RAM!!! That is so crazy!! The exact number is about 22g(16g RAM + 6g Virtual Memory). But I only play 14days single-player in this save. Using virtual memory won't lead to errors. But it will make your FPS lower. Because virtual memory is much more slower than RAM. The best PCIe4.0 SSD is much more slower than the worst DDR4 RAM. If your game's FPS is not very low but it looks lag, or you can play 7dtd smoothly but it becomes lag after days in game, you may need 32gb RAM Image here