Noob with weird overclock numbers

As my first post of Overclock.net, I just want to say that this site rocks.
That being said, I have a few questions on my current pc.

I have an AMD Ahtlon X2 5000+ AM2 processor (Brisbane, G2) (non Black Edition) and I only have the stock cooler, though I do have a one from a socket 939 that looks beefier and I may be able to swap.

I also have two sets of G.Skill memory arranged as:

2x1GB G.Skill DDR2-800 http://www.newegg.com/Product/Produc...82E16820231098

2x2GB G.Skill DDR2-800
http://www.newegg.com/Product/Produc...82E16820231122

for a total of 6GB.

My Motherboard is a Biostar TF8200 A2+
http://www.newegg.com/Product/Produc...82E16813138113

and my PSU is a Rosewill 500W
http://www.newegg.com/Product/Produc...82E16817182076

And I have a 9800GT but I am not overclocking it, yet.

I have a few questions regarding my experience in the last two weeks that I've been trying to overclock this computer.
For one, I have tried the overclocking guide on this website for AM2+ motherboards. When I tried the see how far the motherboard's reference clock would go, I could never go beyond 300 mhz. I lowered my HT multiplier and increased the voltage but nothing. I manged to get to 3120Mhz on with a reference clock of 240 mhz but could never get Orthos to go past 8 minutes without upping the voltage. But upon upping the voltage, I managed to hit 60 deg. under load. I understand that I can't push my stock cooler too far and that I am at a disavantage in using all my memmory banks.

The Problem:

First:
I am stable right now at 3Ghz 1.296 Vcore. But I believe I have a problem. CPUID Hardware monitor shows that I have a -7.42 voltage reading on my -12 rail. Is this normal?

Second:
I can never get a solid reference clock reading on CPU-Z. It always over estimates and reports my reference clock about 1.3 mhz faster than its supposed to.

Third:
I sometimes get weird readings off CPUID Hardware monitor. This includes a max Vcore of 3.22v (which is locked in the bios to 1.296v). Other times I get a weird temp reading of 89*C and that my CPU fan went to 16k RPM. Other times it reports that I have a negative temp, but this is only for a split second. Ofcourse it gets logged and I see it later on.
Would too much voltage on the Northbridge or maybe on the HT link cause this?

Right now my voltages are in the pictures