[G4] G4 overheating?

[Kevin Willis]

	I am wondering if my Gigabit G4 is overheating.  I replaced the stock 
400 Mhz CPU with a Sonnet 1 Ghz CPU last week.  I had the system lock 
up on me last Saturday night after some extensive game playing.  I 
haven't ran it very hard all week.  Mostly checking e-mail and surfing 
the net.  It worked fine all that time.  I decided to work it a little 
harder this weekend to see how it handled it.  I fired it up about 8:00 
PM last night and have had it running ever since.  It has mostly been 
running at idle... nothing very taxing until tonight.  I started 
playing "Max Payne" for about 2 hours until the game crashed.  I 
restarted the game and it crashed again.  So, I quit that game and 
tried another game.  Less than a minute into that game, the whole 
system locked up and I received one of those Kernel Panics.  I received 
  a similar message on my sons iMac a while back.  After a little 
investigating, I finally put the little stand thing on the bottom down 
so the computer was up off the desk which improved the air flow.  I 
have had no problems with that one since.

	I am wondering if I should add a CPU fan or not. If it needs a fan, 
can someone recommend a place to get one and a type to look for?    
Also, is there a program that monitors the CPU temp?

Thanks--

Kevin