https://imgur.com/a/eLSTFb2
The performance impact is not neglectible. It is extreme.

mmmm, I'm not seeing any performance issues one my side. Also, by looking at the pictures, you're using an old version of this mod (The "Custom architect icon" is no longer a thing, since you can now move any tabs, change it's size and change it's icon.).

However, there is a small impact on the performance, that it's equal to having the Architect Menu perpetually open (so, almost negligible). That impact is caused by the Designator Bar drawing the Designator Icons. I use almost the same algorithm as the architect menu to draw the icons, but I will try to simplify it a little bit more on future updates.

If the Designator Bar is causing you noticeable performance issues, then you may want to disable it, and use another mod like [ur=https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2194026191]DEHotkeys (Continued)[/url] to take care of the shortcuts in main menu.