impact of disabling firewall on performance?

[h bagade]

Hi all,

I've heard that disabling firewall with commands or setting related sysctl
parameter wouldn't increase performance and still firewalls participate in
forwarding process. The only way to reach a better performance is making
firewall modules to being loaded dynamically and thereafter unloading
firewall modules!
I want to know is it right? and if so, why it should be like this?

Thanks in advance