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.
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.
Overclocking since 1978 - Z80 (TRS-80) from 1.77 MHz to 2.01 MHz
bad links. none of the newegg.com worked and the benchmark one dident work aswell
the tomshardware one was just to the forum. not the "HOWTO: Overclock C2Q (Quads) and C2D (Duals) - Guide v1.6.1 "
as i guess u wanted to give me a link to.
if i just want to oc my cpu to 3 gigs. would i need a new cooling system?
atm i just got a normal intel fan spin for my cpu+ Raidmax Sagitta thingy.
Depending on where you live.....
Because it depends on the ambient temperature where your PC is. If you live in a tropical climate, you'd probably get 65C at 3.0+ GHz, farther up north it'd be lower.
By the way, 65 Celsius is the max recommended temperature for your 6420.
Though you'd never really know until you try. Try to clock it up higher until you reach 65C (at load) or start crashing your PC because you don't want to increase the voltage anymore (probably because you've reached the maximum safe voltage). Whichever comes first.
Effectiveness of the HSF is based on the delta between the ambient temp and the core temps of your 2 processor Core 0 and core 1.
The temp you indicated is with the proc pretty much at idle. 35 C, depending on your room temp may be a little high, BUT the temp you want to look at is How high does it go when you load the proc up.
Ex: I have the 6400 @ 3.2. Right now my Idle temp is approx 30 C Room temp is about 18 C. When I run TAT @ 100% load my core0/1 go to about 50 C, This is the temp you want to look at to determine if your HSF is OK. Case cooling and GPU play a big part in CPU temps. If you put a toaster in your Case (OOPs I mean a High end GPU), you need very cook case cooling. My self I monitor case temp, Which normally runs 4 to 5 F above ambient room temp.
An alternative ito TAT is to run Prime95 using small FFTs for about 10 to 15 mins (Not Prime 95 will not load procs to 100%, probably 90%)
My take on the stock Intel HSF - NOT THAT good. There have been many posts, back in the E6300/E6400 era, complaining about the Stock HSF, Many because they could not / did not install properly. That aside, its still poor.