Tiger 10.4.11 is really too old for modern internet use.
Tiger isn't the problem. It's hardware limitations.
TenFourFox -- It's a port of the latest FireFox to run on older hardware and software.
"World's most advanced web browser. Finely tuned for the Power PC."
-- works for me on 10.4. Supports 10.5
http://www.floodgap.com/software/tenfourfox/
alternative download site:
http://www.macupdate.com/app/mac/37761/tenfourfox
Turn on pipelining. This will allow Firefox to make simaltaneous requests to the server. Chrome has pipeling turned on. Some sites could fail to load with pipeling set on. The site will be old. See "Increase pipelining" in:
http://www.hongkiat.com/blog/firefox-optimization-tips/