I’ve noticed that some internet applications (like newgrounds) lag a lot when im using Ubuntu installed from Wubi. Is this because it doesn’t have a dedicated partition? If I delete windows, it would work faster, right?
You are correct in the assumption that Ubuntu runs slower because of Wubi. This is because it is inside of your Windows operating system. However, you do not have to delete Windows; you can set up a dual boot system. Search online for instructions, but basically Ubuntu will resize your Windows partition and then install on the space it frees up. It then gives you a boot loader to select your operating system.