Same Problem.

I have deleted my Endless Space 2 folder in Documents and have made the game run as administrator. I then ran a game again and got this:

When I turned forced 1080p UI the game lagged every 10 seconds like described. I turned on automatic and it would only lag when opening UI stuff in the game. Also selecting a race at the start also lagged every 10 seconds when the menu was open. 

Game Version: 1.0.1 S5 GOLD-Public

Diagnostics - 2017'05'19 @2040'19''.zip

AutoSave 94.zip

Radeon Software Version - 17.5.2
Radeon Software Edition - Crimson ReLive
Graphics Chipset - Radeon (TM) RX 480 Graphics
Memory Size - 8192 MB
Memory Type - GDDR5
Core Clock - 1303 MHz
Windows Version - Windows 10 (64 bit)
System Memory - 16 GB
CPU Type - Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz