Some questions about voltage, BIOS settings, and other things

CPU: i5-750
HS: Cooler Master Hyper 212+
PSU: OCZ 550
MB: Gigabyte P55-UD2
OS: Windows 7 Ultimate

http://content.imagesocket.com/images/godzealot01a.png

I'm a newbie overclocker, and I have just put together my system. I followed the sticky guide on the i7 overclocking, and it seems to be working fine for my i5. I did everything in that guide but I never touched the voltage so it's all auto (the guide mentions the safe i7 voltage but I wasn't sure what the i5 safe is, so I just didn't touch). Right now, I am running at 3.8GHz, and Prime95 seems to be stable, it's been running for maybe 30 min.

So I got a few questions...

What is safe voltage for the i5?
Voltage on Auto is bad right?
What is Temp1-3 in Speedfan mean?
Why does my idle temp go down to 13-15C when other people say its in the 30s? I think I must have left a power save on?
After 30 min the max temp I've seen is 38-42C. Does that mean I have room to up the voltage more and see if I can squeeze 4GHZ or more?
Also what other BIOS settings can I tweak?
Am I doing it right?

Thanks

Lol comp, nice post

Thanks

I don't know whats up with Speedfan, maybe I Dl'd the wrong version. Real temp is showing real temps now. The cores are 27-32 idle and my max after 30 min of Prime was 50-53C. Set the volt to 1.296 @ 3800mhz.

I tried to use the same volt @ 4000mhz but prime core 1 errors right away, and the other cores error after a while too. Though it's strange, my computer and cpu temps seem to be fine, and I'm typing this reply @ 4000 mhz as we speak. Only Prime bugged out.

Gonna raise the volt a bit I guess and see what happens.