That voltage looks normal. The voltage set in the BIOS usually isn't what's going to be the actual voltage while the computer is running. If you have anything in the BIOS that says "Turbo" or "A.I. Overclock" then disable it. That might be causing the voltage to adjust itself for stability. 1.488v won't harm the CPU at those temperatures.
Quad core Phenoms, like yours, will generate less heat than a Hexa core which is why the voltage is more on a quad core and less on a hexa core.
I've overclocked Dual cores (above 4.0Ghz) and Hexa cores (above 4.0Ghz) and never seen temps that high. Personally, I think your cpu fan is inadequate. 50C is very high!!! I never see reached 45C even at 4.2Ghz and extremely high voltage.
My opinion: You should invest in a better cpu fan. Do some research. Go to Frostytech.com and find the best cooling you can afford. You don't need liquid cooling as I am not convinced that most liquid cooling does anything more than good air coolers. Let me know how it works out.
FYI: I use the Tuniq Tower Extreme and it is awesome!