We just upgraded to SolidWorks 2025 from 2021 last weekend. And we have a serious problem with Large Design Review Mode.

We have an assembly that will open in about 15 seconds in Large Design Review Mode. It takes about 3 minutes to open in Lightweight mode. Sounds like a good case for LDR?

Problem: Switching to a subassembly in a different window is no problem. HOWEVER, switching back to the window with the first assembly that's in LDR takes over 5 minutes. 

• Open in LDR, 15 seconds
• Open in Lightweight, 3 minutes.
• Switch back to window in LDR, 6 minutes.
• Switch back to window in lightweight mode, 5 seconds.

This LDR (Large Design Review Mode) makes no sense in 2025. We did not have this problem in 2021.

I've seen this problem with a couple of assemblies today. The smallest one we have the problem with so far has 4591 components.

Working with SolidWorks Premium 2025 SP5.0.

Any suggestions?