I have CrossFire and SLI working with Arena Commander.
1. Start the game, and press ~ to open the console:
2. Type in the following commands:
r_MultiGPU = 2
r_MotionBlur = 0
r_vsync = 1
r_buffer_sli_workaround = 1
sys_maxfps = 30
sys_maxfps needs to be tweaked, I have mine set to 120 which runs flawlessly, but your rig will be different.
If this does work, and it should due to the bug that is causing the textures to "glitch" then you should create a user.cfg with the listed commands in your starcitizen folder.
Your a PC gamer. Act Accordingly.
Note: For whatever reason, r_vsync must be enabled, despite it not locking the framerate.