Newbie having problems with noisy fan and high CPU usage in Activity Monitor

Question

I am new to the world of Apple and have got my hands on a hand-me-down PowerBook G4 version 10.4.11. It works fairly well for everything but the Internet.
One of the first symptoms i noticed was that watching stuff on youtube was slow and jumped a lot. I checked a few things out and looked the CPU usage in activity monitor and this was about 80% to 100% when on youtube or even moving from page to page. I'e tried loads of stuff including repairing disk permissions, emptying caches and relaunching finder when the preferences file is on the desktop (not really sure what that was supposed to do).
The next thing I discovered was that if i disconnected the laptop from the mains and played youtube and some other applications the whole thing would go into sleep mode very quickly. I have got temperature monitor downloaded now although I already know it is getting very hot.
PS when it heats up the fan turns on because I can hear a whirring sound...
Would really appreciate some insight into this as it seems to be a good runner otherwise.
PS2 I have loads of free space left in the disk usage tab in activity monitor.
Big thank you in advance

Answer 1

Welcome to the world of PowerBook!
One of the first symptoms i noticed was that watching stuff on youtube was slow and jumped a lot. I checked a few things out and looked the CPU usage in activity monitor and this was about 80% to 100% when on youtube
Virtually no G4s are dealing well with web video anymore. The video technology used by modern developers puts a huge strain on a G4 processor. As this a choice made by coders, there is not much you can do about it. Some people suggest adding RAM but the effect is marginal considering it's the processor that's taxed.
Notebooks get hot. The fans in my 1Ghz 17-inch PowerBook from 2003 kick in between 130 and 140°F. The danger point is not until in the vicinity of 100F so don't sweat it to much. Make sure you do not cover the case bottom by setting the computer on a thick cloth placemat, pillow or other bedding item, or on your lap without a lapboard. The bootom of the case is part of the heat dissipation system and needs air under it to work
A lot of PowerBooks have, by now, lost some or all of their "feet" that gve a little space under the case. Don't bother looking for official replacements--get the silicone door/drawer bumpers from the hardware store that stick on. I found some about 3/16" thick that let more air under my PB thatn the mostly missing originals.
The next thing I discovered was that if i disconnected the laptop from the mains and played youtube and some other applications the whole thing would go into sleep mode very quickly
Your battery is likely dead from old age. Batteries only last about 2-3 years. You are seeing a sign of the battery lacking sufficient remaining capacity to run the computer. Get this utility:
http://www.coconut-flavour.com/coconutbattery/
(you'll need the 2.6.6 version for Tiger) and post what is says about "Health" and "Cycles."