I have just built my first rig and I am currently working in the BIOS stuff. I have a P5N-E SLI Asus motherboard so it has options for overclocking and I was wondering to what degree would be safe. I have been looking at the articles here on the website and they are helping alot, but I kinda wanted to run this by some people first. I can do research by my judgment may be off by a good bit. I have:

9.8 inch fan in the case side that pulls air out
X dream 4 CPU fan that has 2200 RPM with an airflow of 33.75 CFM
Fan life is 40,000 hours.

I also have a 550 power supply that comes with its own fan.
Oh yeah and the CPU is a 3.4 intel dual processor.

I am thinking that with such big fan (9.8 is pretty freaking big) and a good CPU fan, I can get a bit of overclock without much damage. I am totally unexperienced so how much is safe? I read up on the cons of overclocking and I am willing to chop that cpu life expectancy down by a couple of years, but I don't want to have to go out and buy a new cooling system or worry about babysitting it for overloading. I just want to overclocking enough to get a little extra juice, but not have to checking to see if it is overloading. The bios allows me to set the overclock speed by percentage (I don't know if that is unusual or not) but that does allow me some precision (at least I assume).

Like I said I am new to this, so I may have told you what you don't need to know and nothing you do.

We can help more but we need to know the EXACT model CPU you have. Is this a modern core two Intel or an old Pentium 3.4?

Generally, go for it. It's actually very hard to damage a CPU by overclocking. CPUs last a LONG time. Decades probably. Overclocking may reduce the life span due to a gradual degradation called electromigration, perhaps by a significant chunk of the lifespan, but nobody runs CPUs long enough for this to be an issue.

Sudden or rapid damage is possible but for this to happen you would need to do something either VERY aggressive or very stupid.

For example, overvolting the CPU is a common means of squeezing out a higher clock than otherwise possible. If you overvolt it well past what is considered safe then this might damage it. But a reasonable overvolt is known to be quite safe. However, overvolting isn't even needed for a modest overclock.

Forgetting overvolting for a moment, lets assume you just turn up the clock speed. If you push the CPU clock speed too far the CPU will overheat and if it overheats enough and for a long time this could damage it, but before this will physically damage the CPU the CPU will start generating errors, your system will crash, and you will back off the clock a bit until you get it stable. This is how a stable level is determined in fact. It's a built in safety factor.

The smart thing to do is to follow a guide for your particular CPU and stay within the guidelines. To be extra safe you can monitor your CPU temperatures with many free utilities. So long as you stay within reason damage is almost impossible.

Again, to help more we need more details.

There are no modern Intel CPUs that come at 3.4GHz stock. It must be pre-C2D, which means it already runs hot.

It probably is a Pentium D.