Stuttering / Frame drops with RS880/785G and AMD Bulldozer CPU

[Shahar Or]

Dear Ones,

Since replacing an AMD Sempron 140 with an AMD FX-4100 CPU in my
system I'm experiencing frame drops in practically anything. They seem
to be CPU activity related and they are very frequent.

I've reported this is bug #927918 in Ubuntu:
https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/927918

Please let me know if you think that this could be radeon driver
related or something else because I really don't know where to
start... I even looked at the AMD cache penalties bug:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/862583
But it shouldn't make such a big noticeable problem, right?

The BIOS is latest version. I've also tested FGLRX and that gives me
low framerate in Ubuntu compiz so I'm not sure if there were frame
drops.

Blessings,
Shahar