I think I figured out what is going on here. I am not 100% sure and I am by no means the brightest bulb in the light shop, but I think our motherboards (or in my case the ASUS P5E3) might be sending high voltage for FSB Termination.
I had a read of this QX9650 Datasheet

Now, I don't quite understand the whole electrical technical data, but it looks to me like the FSB Termination Voltage should be ~1.15V Max?
Now the minimum I can set FSB Termination Voltage on my P5E3 is 1.20V
CPU PLL Voltage it reads like the maximum Intel suggest should be no more than 1.55V?
The minimum my ASUS board will let me select is 1.50V
I was naive thinking that FSB Termination of 1.38 and SPU PLL of 1.56 were safe, but not anymore.
John