Need advice on overclocking Core 2 Duo 3.0GHz E8400

Okay, i'm a total noob when it comes to overclocking. So this is the reason why I need some expert advice. Was thinking between 3.5GHz to 4.Ghz

To start, let me give you my system specs:

CPU: Intel Core 2 Duo E8400 3.0 GHz
Motherboard: EVGA 680i SLi SE (TR version)
Memory: OCZ SLI-Ready Dual Channel 4096MB PC6400 DDR2 800MHz
EVGA GeForce 8800GTS 650MB Superclocked x2
Windows Vista Home Premium 32-bit
Not sure of brand of power supply but it is SLi certified at 900 watts

I have the Nvidia system tools application so should i be overclocking with this or should I overclock within the Bios at startup?

thanks

Like DellUser1 said, this should be your first stop:
HOWTO: Overclock C2Q (Quads) and C2D (Duals) - Guide v1.6.1
http://www.tomshardware.com/forum/ [...] uals-guide

This should be your second stop. You need to know something about thermal management or you can fry your CPU. It's actually kind of difficult to fry a modern CPU, but it is possible.
Core 2 Quad and Duo Temperature Guide
http://www.tomshardware.com/forum/ [...] ture-guide

Third stop will be a guide for your particular motherboard. Google is your friend.

You should be able to reach 3.2 - 3.3 GHz with the stock heatsink. For anything higher, you will need better cooling. Here are two under $50 heatsinks that are pretty popular:
Sunbeam
http://www.newegg.com/Product/Prod [...] 6835207004
Xigmatec Dark Knight
http://www.newegg.com/Product/Prod [...] 6835233029

They both require a somewhat different approach to applying thermal compound.
Suggestions for applying thermal compound:
http://benchmarkreviews.com/index. [...] mitstart=5

And they are pretty large, so they might not fit inside your case.

Go through the first two threads. Do not do anything until you have a good idea about what you are trying to do. Once you have definite questions (you will, you will ), come back and ask.

Keep in mind that these are guides, not cookbooks. YMMV. Your Mileage May Vary. Because of all the variables, you may not do as well as someone else with a similar system. Or you might do better.
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Overclocking since 1978 - Z80 (TRS-80) from 1.77 MHz to 2.01 MHz