Steps to reproduce:
1. Open user-attached project
2. Build with both Mono and IL2CPP backends
3. Follow the instructions provided in 'Notes' to connect

Expected: the performance is the same in both the IL2CPP and Mono versions
Actual: the performance is way slower on IL2CPP

Reproduced in: 2018.1.8f1, 2018.2.0f2

Unity 2017 was not tested due to windows IL2CPP not being introduced yet
Unity 2018.3.0a4 could not be tested due to crashing

Could not build to OpenGL due to this error:
"Unspecified error during import of AudioClip Assets/Tayx/Graphy - Ultimate Stats Monitor/Scene/Audio/SFX/269180__mickleness__chat-message-1-incoming-message_01.mp3"

Notes:
open 2 clients/windows.

#On Window/Client 1
/login test1 test
/conn 101 1
/state lobby
/room create hangout duel 1

#On Window/Client 2
/login test2 test
/conn 101 2
/state lobby
/room join id_of_hangout_room_id

#On Window/Client 1
/room ready
/room start