Game (especially CAS) lag issues

I have a terrible lag that makes the game absolutely unenjoyable. I thought a new install might help and if I'm playing with a brand new install, it's okay. But when I put back my saves, lag hits again. I tried to make a new family, start with a new town but nothing helps. Gameplay is kinda laggy but the real problem is CAS.
The game stops for minutes when loading a set of items (eg. male tops) and I can't do anything meanwhile. If I click to another category (eg. male bottoms), it stops again for a ridiculously long time till it loads. Going back to a category that has been loaded before means I have to wait long-long minutes AGAIN, despite I've done that before.
Any ideas how to solve this issue?

Hello,

As a matter of fact, there is something you can try that can help you fix the CAS issue specifically. 
Have a look at Master Controller, with that mod you can activate a simpler CAS-mode, which will basically just show you 1 of each in stead of 3-4-5 different colours for each item. 
If you follow that link, you can read more about it, how to use the mod and download it. 
If you're unfamiliar with installing mods, try our handy guide here.

The specific interaction you're looking for is "show in compact form .." from MasterController's CAS menu. You can find it in map vieuw > click city hall > Nraas > Master Controller > Settings > CAS.

Good luck, and let us know please if that helps!