Please have a read of the
first part of the guide, if you haven't already. It will answer a lot of questions, and make your overclocking experience smoother, and hopefully more enjoyable. In this part of the guide onwards, I will assume that you have read and understood
Part 1.
Hopefully, now, you should now have an idea of what we are trying to achieve, and we can get down to business!
I am going to be using the Asus P5K Deluxe WiFi AP for reference, a Q6600 and I will provide as many BIOS screen shots as possible, so you can easily see what I have done.
Ensure that you have the latest BIOS for your motherboard (311 at the time of writing this,
available here.
In pic below, you can see that we have manually entered the RAM timings and voltages. (I know I keep going on about this, but the amount of questions I get asked, that end up being fixed by this is incredible!).
In the screenshot, you can clearly see all the main timings for the RAM. It is important that you enter these to get the best performance from your RAM. If you don’t enter these timings manually, the motherboard will read the SPD table of the RAM and run it at the standard, relaxed, safe, timings. This is OK, but not optimal, and as you have a motherboard that is a RAM overclocking monster, there should be no excuses
While we are in the BIOS, disable anything that you aren’t using, this part is optional, but I always do it. Things like on-board sound (if you have a sound card), Firewire (if you don’t need it), IDE controller (if you don’t have any IDE devices)….you get the idea anyway!
If you have a separate PCI RAID card, and are experiencing problems with drive detection, try disabling legacy USB.
Save all that, boot to windows, check everything is working OK and then back to the BIOS.
Next, we are going to set the RAM at 1:1.
I found a strange bug while writing this, which may or may not be specific to my setup;
At the moment, the P5K displays the 1:1 RAM settings incorrectly, which might be a bit confusing for some, so I will try and explain what is going on, and hopefully they will fix it with a BIOS update. Lets say that you want to have your FSB running at 266 and your RAM running 1:1, this would normally be shown as 533mhz for the RAM (on, say, a P5B etc.).
There is a bug (might be intentional, who knows?) in the P5K BIOS that only allows for a minimum of 667mhz RAM when the FSB is under 300., it appears as if the board is running dividers for 1333FSB CPUs (quick bit of maths, 1333, roughly divided by 4 = 333, and that would explain the 667 RAM...anyway!) A quick table to illustrate. 
As you can see, up to 300 FSB, the 1:1 divider is running at odd speeds, that you wouldn't normally expect, but as we will be running higher than 300 FSB, this wont affect us, but it is always good to know stuff 
As we already know your system is 100% stable at stock speeds (
see Part 1), we can now go for the jugular
(well, ish)
Set the FSB to 333.
The RAM will stay at 667mhz. Why? Have a look at the table above, this is fine.
Set your CPU voltage to AUTO for now, later, we will come back and set it manually.
Save and exit the BIOS and let it boot to Windows.
When windows has finished loading, open CPU-Z (it will take a few seconds to open), have a look at the memory section of CPU-Z as well, it should be the same as the timings that you entered in the BIOS earlier, something like this...
After you have finished marvelling, you can close CPU-Z, it was just to show you the changes that you have made.
As in
Part 1 of the guide, run a stress testing program such as
Orthos/Prime/SP2004, or if you are using a quad CPU, and Orthos/
Prime/SP2004 crashes, try 4x instances of
SP2004 Just create 4x separate folders and run each of the exe files from the folders, and then set the affinity for each of them in windows Task Manager. Each instance of SP2004 should be assigned to a single core, in the pic below, you can see the first one assigned to core 0, the next one should be assigned to core 1 and so on.
OCCT is a good stress test that will create a lot of heat, and stress all four cores, and can often give you a good idea if your overclock is going to be stable.
Set Orthos/Prime/SP2004 going and read this next bit, and remember to keep an eye on those temps.
A note about temp monitoring software I have seen a lot of people stressing about their temps recently, and there's really no need to.
One thing to keep in mind is that pretty much every CPU reports temps differently, some report them MUCH higher than others, and there really isn't much that you can do about it.
If you suspect that your CPU is running too hot, simply feel the heatsink while the CPU is under load, is it very hot? If it is, then you may have a problem, if it isn't, then you probably have a CPU that is reporting too high.
If you have a quad core CPU, it will obviously run much hotter than a dual core CPU, and when overclocked, the temps can get quite high. My own Q6600 runs hot, and at stock speeds, using the stock cooler, it can hit 70c under load with ambient temps of around 23c. As you know, the stock coolers are no good for overclocking. Ask on the forums for advice on the best cooling for your needs.
As mentioned in Part 1 of the guide, there are quite a few things that you can do to lower your temps, and some of those include;
Use a good quality thermal paste like Arctic Silver 5, and follow the manufacturers instructions on how to apply it. Different CPUs require a different method of application.
Properly secure your CPU heatsink. Make doubly sure that all the plastic lugs are pushed in as far as they will go, and then turned fully clockwise to lock them, otherwise, when you stand the case up, one or more of them will pull out. (see the troubleshooting guide for instructions on how to do this properly).
Make sure you have good airflow through your case. You need a minimum of a fan at the front drawing in cool air, and a fan at the back exhausting hot air. When you overclock, you generate extra heat, which must be somehow got rid of. Side fans, and top fans can also help, its just a case of experimenting to see what works best for your set-up
Reduce cable clutter in your case. If your wiring is all over the place, this will restrict the airflow dramatically, and your temps will rise.
I use 3 temp monitoring programs myself, and each have their own merits and drawbacks.
If running a dual core CPU, I use TAT (Intel Thermal Analysis Tool), Coretemp and Asus PC Probe 2. I use Asus probe solely for keeping an eye on voltages, and the Northbridge temps, and TAT and Coretemp for the CPU temps.
These work for me, however, some people can't get them to work. Vista seems to be a problem area for some temp software, and some boards, such as the 680i boards seem to be fussy about what they run as well.
Be aware that if you use Speedfan to monitor your temps, your CPU temps will usually be around 15c too low, which could be dangerous if left unchecked, and for that reason, I don't recommend that you use it until they fix that.
CPU-Z is a great little program for a lot of system info, but avoid using it for monitoring your CPU voltages when overclocking, as it incorrectly reports them.
I'm running a Q6600 on this P5K, and I have found Coretemp to be the most reliable with this set-up I also use Asus probe, as I mentioned above, for voltages and Northbridge temps.
Ok, so now it is 6 hours or more later and Orthos/Prime/SP2004 ran fine with no errors (If it didn't, please see the
troubleshooting guide), so next we can up the overclock again
Go back to the BIOS.
Lets try a higher FSB, shall we say 380 FSB? (Keep in mind that some CPUs wont go this high, so don't worry if yours doesn't, just set the FSB slightly lower and try again.)
Set to 380 FSB, the RAM will auto adjust to 760mhz (I'm assuming here, that you have RAM that is capable of at least 800mhz (DDR2-800/PC2-6400).
Leave everything else as it is, and then save and exit the BIOS.
All being well, Windows will load, and you can open CPU-Z. You should see something like this..
You will notice that your CPU is now running at 3420Mhz. (maybe 3219Mhz)
Also look at the RAM speed, it should be 780Mhz.
As before, run Orthos/Prime/SP2004 for around 10-12 hours, if it passes with no errors and you are happy with the temps, then there's no reason why you cant try for higher, although for most people, even 3420Mhz is more than enough for most things, but, if like me, you have the bug, then go for it.
If you didn't pass Orthos/Prime/SP2004, there are a couple of things you can do;
Boot to Windows, and make a note of the voltage displayed for your CPU in Asus probe, go back to the BIOS and manually enter one notch above that voltage, so if Asus probe says 1.4v, change it in the BIOS from AUTO to 1.4125v and test again, if it still fails, you can try another notch until it is stable, but keep an eye on those temps.
Or,
Lower the FSB slightly, you can drop the FSB in increments of 10, and test with Orthos/Prime/SP2004 in between each step until stable.
Got all that?
Onto Part 2.
continued below.....