slow unless the CPU is in use

I have a HP Pavilion dv6258, which has an amd turion X2.
Installed current as of yesterday, and noticed something quite odd.

Things are pokey slow, hit a key and wait a second or more for it to
appear on the screen. Long load time,takes forever to shut down all the
processes, as a whole it's crawling. However if the system is doing
almost anything, like compiling a port or recompiling the kernel,  or
just downloading a file during a port, then things are what I'd consider
a normal response. I recompiled the kernel and removed all the various
debugging options, same symptoms.

I recompiled with SMP removed, the kernel no longer finds 2 CPUs, but
the same issue.

This was a 6.2 to 7 upgrade (using mergemaster, etc), I haven't tried to
a straight current install as of yet. Any suggestions on what I should
try to correct this behavior?

Thanks,

Keith