Remove "Users Online" box completely
 

I want to remove the "Users Online" box from my entire website, and if possible turn off X-Cart from gathering this data (to improve performance)

Not sure what XC version you're using, - but in 4.0.13, you can just disable Users online in the admin:

1. Log into /admin
2. Goto administration / modules
3. Disable 'users online' and submit

If you're after performance gains, I think there are some threads floating around in disabling Statistics too.

Cheers,
JB

Disable Users Online
 

Thats exactly what I was looking for!! :D