The How To

Now that we have an understanding of the hardware and the software that controls it, lets put it into practice. The most important things is to go slow and work your way to find the limit of your hardware without doing any damage. It's always good to have a goal in mind when overclocking, decide if there is a certain CPU speed or maybe a certain FSB you want to reach. I'm going to give your a few scenarios that will give you an idea of the different ways you can overclock your system to attain your overclocking goals.

Scenario I

In the software section we mentioned overclocking with the multiplier and we also mentioned overclocking with the FSB. It's possible to use both methods simultaneously and is often preferable in some situations. For example on an 1800+ you might increase the FSB from 133MHz to 166MHz and increase the multiplier from 11.5 to 12. It may also be necessary to increase your Vcore at the same time; go very slow here increasing just slightly above the rated core. Now reboot your system and if everything goes well the system runs at 12 x 166MHz which results in a 1992Mhz system running at an 333MHz FSB.

Scenario II

In this scenario we'll Increase the FSB of the computer and lower the multiplier. Again using the 1800+ as an example we increase the FSB frequency from 133 to 200 MHz and lower the multiplier from 11.5 to 11 in order to attempt a 400MHz FSB.* Now we set our Vcore up a few notches and reboot. If everything goes smoothly your system would now be running at 2200Mhz with a FSB of 400Mhz which in AMD terms is a 3200+. Notice we lowered the multiplier this time. The reason for this is because in this case we desired to reach a 400MHz FSB but the system wouldn't boot at 11.5 and rather than compromise our desired FSB we lower the multiplier to accomplish our goal.

*I know to some of you this seems extreme and users should NOT go directly from 133 all the way up to 200. Move the Mhz increments up slowly. With good cooling, a good chipset and adequate RAM this possible.

Scenario III

In this Scenario we'll use an AMD 2500+ Barton. Our default for this chip is the BIOS is 11 x 166MHz. We'll increase only the FSB to 200MHz and leave the multiplier at 11 then raise the Vcore slightly from 1.65 to 1.70, now reboot and we are running at 2200MHz with a FSB of 400MHz. Since we increased the Vcore very modestly our core temperatures barely increase, which is good for the all around health of the system.

What if my system hangs or won't boot?

This is quite common when overclocking and indicates that either something in your settings needs adjustment or that the overclock is simply not possible.

First lets look at how to get out of a hung system or a system that won't boot. The first thing you can try upon a failed boot is to repeatedly hit the delete key to enter the BIOS. Another method that some systems employ is a default reset that will let you into the BIOS by temporarily lowering the FSB, for instance hitting the insert and delete key repeatedly on some systems will achieve this. If your system isn't so equipped you may have to resort to clearing the BIOS by either resetting a jumper on your motherboard or removing the battery and even both methods sometimes.

Now that you are back in your BIOS after a failed overclock we have to attempt to overcome the problem and retry. So how do you know what went wrong? Was it that the memory couldn't handle it? Was it that the Vcore was too low? Is the multiplier too high? Is the FSB too high? An experienced overclocker often looks for tell tale signs that indicate the problem as the system fails to boot. Such as, where in the boot process did it fail and what was on the screen when it failed often tells exactly what needs to be readjusted when you re-enter the BIOS. Here are some of the signs you can look for

1. A blue screen when booting almost always indicates a memory issue
2. Rebooting in Windows or when just about in Windows maybe too low a Vcore or overheating due to excessive Vcore
3. A system that beeps or hangs when first rebooting likely has multiplier or FSB configuration that exceeds what the system can handle
4. Syntax that comes on screen when booting indicating a file that can't be found or is corrupt is likely due to too low a Vcore

While these signs aren't always a certainty and may vary with some systems you can us them as a guide when investigating your problem. Now lets look at how to solve some of those problem.

1. First the memory problem, if your system has a blue screen when booting you can try going back into the BIOS and either lowering the FSB to something that is more agreeable with the memory or you can try and help the memory to overclock by increasing the Vdimm thus adding more voltage. You may have to try both and see what one works best.
2. Now lets look the next scenario where get in to Windows or almost get there and your systems reboots. If you set your Vcore too high your CPU maybe overheating, but more likely because you are the cautious person you should be when overclocking, your Vcore is too low. In this case go back into the BIOS and increase the Vcore slightly and reboot and repeat if necessary until your systems is stable.
3. Your system beeping or hanging when rebooting usually means going back to the drawing board and trying other multiplier or FSB settings. You could also investigate a low Vcore though this is unlikely and if was the case the amount of voltage needed to get into Windows from a hanging failure would be prohibitive and even dangerous to your CPU.
4. Syntax indicating corrupt or missing files when booting likely is low Vcore and requires you to increase your Vcore in the BIOS and reboot, you may get further but still not into Windows and may have to continue cautiously increasing your Vcore until you are in Windows and stable.

As you gain experience in overclocking you will learn your systems limits and tell tales that will help you achieve your overclocking goals, sometimes it helps to make notes on how you achieved your overclocks and overcame problems.

Testing for Stability

What happens after your system boots successfully into Windows? Unfortunately it is not quite time to celebrate yet. A system that boots into Windows fine when idle is not a sign of system stability. One of our favorite programs for stress testing an overclocked system is Prime95. Prime95 not only stresses your processor and memory but it also checks the results generated from the calculations against previously verified results. This can guarantee that processor and memory are actually working correctly instead of just simply working. An error in Prime95 usually indicates that the Vcore setting is slightly low. If errors still continue, a memory test with Memtest86 is a good way to narrow down the source of the error. A processor should be tested for a few hours minimum, ideally it should be tested for a full day. For the first hour or so do not leave your computer unattended for long periods of time. The processor may get very hot and you may want to stop the test if the temperatures get uncomfortably high. Generally 45 C and below is a pretty good temperature. 45-55 C is getting on the uncomfortable side while 55+ is really starting to push it and care should be taken. If temperatures do get that high it may be time to drop the Vcore or the clockrate down a bit or look at other cooling solutions.

Conclusions

Hopefully we have dispelled some of the myths of difficulty that one may encounter while overclocking as it can be a relatively simple process. But like any serious hobby, overclocking can be very involved due to the little nuances as well as luck. Something we try to minimize with this guide is luck. This comes from doing homework on processors as well as choosing quality memory and having an understanding of what different chipsets are capable of. Key points that we cannot stress enough are patience and caution. Yes it would be excellent if every chip overclocks by 100% right out of the box but they do not and that is a pretty good way to fry a new processor. Another factor is risk. Know that overclocking your processor may shorten its lifespan (from personal experience, having overclocked many processors from both AMD and Intel in the last few years, none of them have died because of overclocking).