[Cube] Thinking about a upgrade

[Francois]

Okay...
So, I've come to the realization (after using a new iMac for some  
time) that I want a faster computer... not necessarily want, but it  
would be nice to scrub pdf's and itunes windows with out hiccups. so  
any suggestions on processor upgrades? or Graphics card upgrades? Im  
looking for 3 things. 1 want to be able to run no fan. ( i live in  
canada and the room where i have the computer never exceeds 25C )  
should be cheap - are the upgrades available used yet? hopefully  
around 3-$400. and reliable. i remember hearing that powerlogics had  
a 1.3Ghz that had lots of problems.

my current specs are:
10.4.8, (runs great btw)
450 MHz
1.25 GB RAM
300GB Segate drive
Rage 128 Pro (16MB V-RAM)

Thanks everyone!
-Francois