I have tried several projects in 4.3, including the included AngryBots, and have run into the same issue with all of them. I get a really great framerate in the Game View, but the standalone builds run extremely slow. The profiler says that the slowness is being caused by constant CreateVBO calls. These calls are not present when run in the editor.
Yes, i too have this issue, it’s on the PC version only though, Mac standalone seems fine. My games gone from 60fps to 15fps! I’ve tried changing various quality settings, disabling shadows, fog etc and the results are the same.
This was getting spammed into my log file…
HandleD3DDeviceLost
HandleD3DDeviceLost: still lost
Skipped rendering frame because GfxDevice is in invalid state (device lost)
since 4.3 I get “Mismatched serialization in the builtin class ‘Mesh’. (Read 183360 bytes but expected 183361 bytes)” error message and YES, I have same problem with performance drop in comparison to 4.2 builts and the 4.3 editor-play within unity.
Now Im not sure if I better switch back to 4.2 until its resolved or if its okay to work on the 4.3 scenes and wait for a fix.
I hope this gets fixed quickly, I resolved a lot of bugs today and made some really nice optimisations to Lunar Flight and really want to get the update release onto Steam ASAP…
Never rely at promises. You have to use what is available now. And that´s Unity 4.2 
For me too, I noticed a bizarre situation of the editor running something at like 60fps and then the windows standalone running less than 30fps and no matter what I did I couldn’t get it to improve. Same project seemed to work fine on Mac and Ouya.
I would like to chime in and say that I am experiencing the same thing. More people on the list, hopefully the faster it gets noticed. I have tried several things including turning off lights completely, I thought maybe it was a light map issue but it isn’t. What’s worse is that my in game and stats gui FPS counter shows 60(vsync in game) and 100+ on the stats GUI but it clearly is not running at such speeds.
Definitely seen a significant performance drop. In case others haven’t noticed, occlusion culling had huge changes made to it. If you are using occlusion culling you’ll need to re-bake it. Though on our end I can confirm its not occluding as reliably as it used to.
The same here… 70-80 fps in Editor … 10-15 in Player… Seams to happen only with upgraded(converted) projects to 4.3… In new created projects with freshly imported assets no performance drop… But after all lets drink a beer for the new Magic Occlusion System 
DDDD
OC is unusable for me. It keeps shutting off visible lights. It also appears to have no effect on performance.
this happened with 4.2 as well, I do not think it is relevant. However I can confirm the lost of performance as well.
My performance in general has been decimated as well. I’m getting 1/4th the performance as before (<30 FPS) in standalone builds. In the editor, I’m getting 3/4 of the performance compared to 4.2 (90 FPS vs 120 FPS).
Make a bug report i woud say. The more test cases Unity gets, the better for them to catch the baddie. So throw them to death with test cases
Same for me, really poor performance with PC builds after 4.3 upgrade.
What Operating System are you using… i’m using Windows 8.1 Pro x64… is there someone with that version of windows to… i am wondering if there is any chance for the OS to be not fully supprted or something like that…
OK, yeah must have just been a coincidence, can’t be good though what ever caused it?
I do hope the get this addressed soon, I am sitting on an update I need to publish to Steam.
Windows 7 64bit here. I’m not sure that is the problem though as it runs fine in the editor.
+1. My game actually runs faster in the editor of 4.3 than 4.2. BUT runs very slow in windows build. Here are the FPS.
In editor: 42-52 fps.
Windows build: 9-12 fps.
Just terrible. Not sure how this bug was missed. Unity, really hope you fix this asap. 
OK guis by me the problem was cause by the static batching system, after i removed the static batching flag on all models now my game runs much faster in Stand alone … : ) just try to disable it for now… until Unity fix the problem…