Thanks guys. I used the SystemLoad, yes (doh!) and
memtest86 . No problems found (I really wanted to test the OWC and Apple RAM).
The CPUs never go above 47 Celsius on high load which is good. Memory idles at toasty 55 and goes up to close to 70 on high load which seems a tad high. Power supply is pegged at 45 no matter what is happening to the system. Ambient air is 21.
x1900XT idles at 55 and goes up to 80 (ouch) in a game. Taught by my previous experiences with PCs I removed the heat sink on the x1900 thinking they used too much cheap grease. I found something that looked like Arctic Silver and it seemed there wasn't too much of it. I applied my own grease and put everything back together only to gain 2 degrees. This is the first time I saw a proper job with the thermal grease out of the factory...
I think I'll hack FanControl to put the minimum fan speed at 600 or 700.