Try this first.

If set to billeanear then swap to Trilinear, and opposite if you are already on tri.
Run the Game in Fullscreen, if you are already running fullscreen swap to window and
open the task manager and increase process priority one step.

Repeating patching of the game.. taskmanager end xsyon.exe restart launcher.

Important tip, If you downloaded patch from certain patch server lets say EU, then use EU for log in as well, if you pick US server for login after you just patched on EU server, it will start downloading same patch again. Same goes for US. Patch servers are not in sync causing the issue

Step 1: Run Windows update

Step 2: Update your DirectX Drivers and your Graphics Drivers (ATI / Nvidia)

Step 3: Delete Options.sav from Savegame folder in xsyon

Option 2: Delete the Zone and Script File. And redownload em from here.

Option 3: Reinstall the Game - Torrent Link here

Other: If you are getting a sound error and can't move, unplug whatever you plugged into your computer and restart the game.

D3D Error: Remove Options.sav from savegame folder inside Xsyon mainfolder

Game Crashing and Forcing Download Each and everytime you launch the patcher?
No solution, but if you do not shut down the game client and just logout to the 2nd loginscreen you are still able to log back in. Warning: You could miss vital patches like this

IF none of the above works, fill in a support ticket and include the crash logs.