I have a 1.0 GHz PB Ti. Replaced the M/B, cleaned the green goo off the CPU/heatsink with hexane and applied Arctic Silver. Removed all the caked dust found in the nooks and crannies, particlarly the fan cages. I added a 120GB SSD from MacSales, plus 1GB of new RAM. My DVD drive was getting a bit possesive towards the OS9 install disk, so I bought a used Superdrive from someone on eBay. Prior to these changes my Ti 1.0 sounded like a 747 on take-off, now it only gets a little warm in extensive use. It sounds as if the fans barely turn. It also runs cooler under OS9.2.2 than OSX 10.4.11 (?). The other import change was to stand the machine off the desktop on 1" rubber bumpers, the sort used under items of furniture. You can buy these in bags off eBay or from your local hardware store if you are lucky enough to still have one. The extra airflow under the bottom of the case seems to make all the difference. This trick also works well on my PBG4 1.67 GHZ alloy 15". I always carry four of these bumpers in my laptop case.