Run away CPU FreeBSD 4.9 Release #0

[Matt Villion]

Greetings, 
I have just installed 4.9 R0 on to new hardware and have encountered an
unusual issue.
It was not detected straight away as everything appeared to do what it was
supposed to do...

Some processes run away with the CPU.  Screen is one of the worst offenders
along with python..
The CPU starts out at about 15% and slowly ramps up to 100%.
As the % ramps up, the priority increases up to about 60
If more than one screen is launched, then the will share the CPU but the
priority still sits about 60.

Any ideas what this could be and how to fix.

Matt Villion