Throttling on Phenom X2 550 BE?!

Hey guys,
I got some throttling problems with my CPU...

I've unlocked the remaining 2Cores fine and it runs really stable @Stock Voltage.
But when the temperature hits 52 degrees it starts reducing the frequency to something like 1Ghz?! (temp messured with lm-sensors under linux as coretemp seems to read only garbage temperatures?)


Mainboard: Asus m4a78lt-m le
Cooler: Thermaltake SonicTower Rev. 2 with 2 1400rpm fans.

Do i need an modded BIOS or something to adjust the throttling temperature? Or does the Asus Board just suck?
Like here: http://www.tomshardware.co.uk/forum/274747-12-throttled ?
But i don't really feel like RMA the board :/

Of cause i disabled any power saving feature i saw in the Bios, but it doesn't seem to change anything...

Any help is much appreciated!

That's really like 65c so yeah, it's going to throttle. You need a better cooler.

AND PS:

Hardly anyone looks here, better repost in the main AMD section.