Is there anyway to password protect a wireless network without using any type of encryption security?

The guys above are right: WiFi is inherently slower than Ethernet, even without encryption.

The computational overhead to do the actual encryption of packets is easily dealt with if you've got fairly current hardware, and would be almost un-noticeable.

If you worry about gaming, there are several config's for improving performance, like QoS, port forwarding, etc.

You could rename and turn off the SSID broadcast and have no encryption...but it's not a solid strategy.

Use WPA2/AES Encryption with a unique random SSID (used as initialization vector element in the encryption algorithm) and a strop random pass phrase between 40 and 63 characters (letters, numbers, spaces, punctuation, special characters). Thats the only way to set up wireless (home) networks in a safe considered way for now.

(tech mode on: if you have a radius server, use it :)

Just a note on turning on SSID broadcast. What this does is turning SSID broadcast off on the router, since to set up the connection one party needs to broadcast the SSID, your clients will do this. It is not a solid security measure.

As far as I know encryption won't slow your internet down enough for you to notice, and I've never heard of another way to protect your network without encryption.

Use encryption. Even if it does slow down your computer, it's better than having all your neighbours using your connection and downloading illegal material at your expense.

Choose WPA-PSK, by the way. Not WEP.