Fusion 360 cannot open a specific project, LAGS AND FROZING

[kostaslazaridis40]

When I open a specific project in my Fusion 360, my computer gets extremely laggy. It takes up to 30 minutes to open the project and my computer freezes or lag while opening this file. This behaviour started when I tried to export it as a step file.  I can open other projects and they run smooth

I have tried the following without success:
-I have clean install fusion 360 (2 times)
-I save it as a fusion file and trying to open it again.
-I copy it to a new folder in my cloud
-I recover an older version from the project 

-I saved it as step file and reimport it. Fusion can open it, but it is lagging, when I try to orbit, extrude etc. 

Please help me, it's a project I've been working on for weeks and now the file is unworkable 

Specs
graphic card->GA ASUS RADEON R9 290 R9290-DC2OC-4GD5ram->16gb
cpu->AMD FX-8350 4.0GHZ 8-CORE
motherboard->ASUS M5A99FX PRO R2.0

Video: https://youtube.com/shorts/FMO5VaNhQJM?feature=share

FUSION FILE:https://drive.google.com/file/d/1HmEFD74Xo_c3aSor6FOXxdmrshkVu5pA/view?usp=sharing

[jeff_strater]

most of the slowness in this model is in the two circuit boards:  "BTT GTR v1.0 v8" and "BTT M5 v1.0 v4".  Together, these two designs comprise almost 80MB of the total 133MB in the design.  Is this level of detail necessary for this model?  I would be tempted to get rid of a lot of the details on those circuit boards, and I suspect the model will perform significantly better.

[kostaslazaridis40]

I have removed them, with no significant improvement. At this point, I have to note that the file was working fine with these files, before the export as step file.

[jeff_strater]

Can you explain what you mean by this?  "At this point, I have to note that the file was working fine with these files, before the export as step file.".  Do you mean to say, that this design, even including these large circuit boards was working efficiently, including open and save, but slowed down after doing a STEP export of this design?  I'd like to find out more about that, since, at least in theory, export of any kind should never affect the source design.  I'd be very surprised to find out that this is true.

For me, deleting those two components did improve the performance, of open, and of view operations, etc.  I notice that there are other details in this design that, if it were me, I would choose to omit, such as threads on the bolts, and the detailed model of the plastic filament.  If those are not critical to the design, I would leave them out.  But, of course, that depends on what your goal for this model is.  If you are going for a realistic rendering of the model, then such details are important, and you have to absorb the cost that those details bring to your workflow.

[kostaslazaridis40]

My design, even including these large circuit boards was working efficiently, including open and save. I was trying to export it as step file and at some point, my computer was lagging and crushing, at this moment I was chatting via discord and I had 3-4 tabs on chrome. As you can see in the video below my pc is crushing even without the components: filaments, bigtreetech PCBs and raspberry 
 https://youtube.com/shorts/bMaWQ_Ypu5E?feature=share
Even, when I close the specific project my pc is crashing 

https://youtube.com/shorts/vT7pIUpDDJw?feature=share 

As you can see, I can open other projects with similar complexity and my pc can handle them well.
https://youtu.be/KJQsvTSu_3s 

[jeff_strater]

the only thing I can suggest is that perhaps Fusion is using too much memory, or is maybe leaking memory, and that is causing performance problems.  Try exiting and re-starting Fusion, then opening a version of this design without the PCBs in it.  It is still a large assembly, and will not be super-snappy, but it seemed to work OK for me.  I suppose it is possible that exporting to STEP could use up some memory, but it should not affect the design itself, I think.

[kostaslazaridis40]

I asked one of my friends to import it, on his pc, it was lagging but not so much as mine. He exports it as a fusion file and sent it to me. Now it works, no super fast but it is acceptable(I deleted a lot of components). The weird part is that this assembly was super-snappy with the PCBs and the other heavy components and now it's not. I have tested my PC, with stress tests, it is performing well. I haven't change any hardware on my pc, I downloaded the latest drivers without any result on fusion performance.     

[LishuangLu]

@kostaslazaridis40 , we have made a couple of performance improvements against Fusion 360. Please let us know if you still feel slowness with your fusion design. Thanks for your support！ 

Regards，

-Lisa