I have experienced this. Take a look at my game running on 2 version
Both cases have Vsync(false); Looking down to skip render overhead
This should not happen.

Current binary build:

Normal: FPS: 110-120
https://i.gyazo.com/e1e9ac78eac4d7fe5124...0a5d83.png

Look down: FPS 200+
https://i.gyazo.com/c44f62f54ddeab50de51...d9530c.png

With source build:

Normal: FPS: 70 - 80
https://i.gyazo.com/6bb6c09aee61130eb7b9...3c2a4c.png

Look down: FPS: 135 - 140
https://i.gyazo.com/8dd5f943dd82d4cdcdc9...e657d3.png

I only export/import .esenthelProject file from binary build to source build and play, no change in code (just remove some removed function of the engine)

btw the shadow smooth still does not work as expected. I cant find solution. this is my old thread about this problem: https://www.esenthel.com/forum/showthread.php?tid=11552

Sorry I don't know.
Make sure you're compiling Release build, and not using Debug option.

Both of them using Debug

With Source build, I try Release option but FPS is the same as Debug option

My card is RTX 2060

I mean make sure in Engine Builder you click default compilation. (not debug)

Hmm... This problem is really serious I think

I rebuilt the Source version with these settings https://i.gyazo.com/05d899f40a0f0f5b8c78...5bdb75.png
Still the same. then I found out something more interesting about this. I recorded 2 videos below:

Note: I use the same project for Source and Binary build. With Source buid, I change a bit about grass view range and godray, not really important I suppose. I use the same (maximum) graphic settings with PiP apply for both case

1. Source build:
https://youtu.be/RWpIn0KQtXQ
- When I run the game from Editor (F5) with Debug option. it gaves me 55-60 FPS.
- When I run directly the executable file was built and placed in _Build_ folder of Source build editor. It gave me ~80 FPS

2. Binary build:
https://youtu.be/DCtvcGQSx_s
At this moment, I did think running editor (Source build) and its executable file at the same time might cause the difference in FPS. Then I tried current Binary build. Surprisingly, running the game from Editor (F5) with Debug option and running executable file directly both gave me the same ~90 FPS

Now you see, same machine, same project, same settings, very different FPS/performance. My computer still seems to be ok with this FPS, but lower spec machine? I think not. There is something wrong with Source build ?

I will prepare my project and send to you private tomorrow. I really want to use the latest Source build, but this problem need to be solved Or at least I know the reason why this happens

Perhaps:
https://esenthel.com/forum/showthread.php?tid=11501
-stencil buffers are now disabled by default, allowing to use higher precision 32-bit depth buffer (drawbacks: Decal.terrain_only not supported, MSAA D.samples>1 is now slower)