Overclocking has been the trend amongst computer enthusiasts for quite a while. This leaves the High-End and High-Clocked components for the conservative users or those too afraid of pushing up a bit the limits of their systems. In this article I will review the essential notions and basic steps on How To overclock your computer.

If you have set up your rig you can skip this part. One of the most important parts is the Motherboard. Whether you go for Intel or AMD you should always buy a solid m0b0. There a lot of manufacturers out there but in my opinion the best boards for overclocking come from: ASUS, ABIT and EPoX. As for the chipset you have a lot of possibilities both from Intel and AMD. The choice is entirely up to you, but I'd go for the 845PE, 865PE or the 875P from Intel and Via's KT600 or nVIDIA's nForce2-ST / nForce2-400 for AMD CPUs. Now it is time to buy your CPU. You should have two things in mind here; first: Never buy the highest clocked CPU available because you won't be able to clock it much further and second: Be sure to check the numbers on the CPU. Because NOT all the CPUs are the same. Some will go for high frequencies and some will run only at stock settings. Here are my suggestions:

• From Intel with the C1 Stepping Northwood Core: P4@2.4C and P4@2.8G.
• From AMD with the B0 Stepping Thoroughbred Core: Xp1700+, Xp1800+ and Xp2100+ or the Bartons 2500+, 2800+ or 3000+.

Other Important parts: The Cooling System. If you go for conventional air cooling options be sure to buy a large, solid Copper heatsink and a 92mm fan. You might want to check some Zalman coolers or SLK heatsinks. If the noise gives you headaches, you can always install a water-cooling system or an air-cooling one. Then there is the Power supply. Be sure to have at least a 350W one. Antec or TT Power Supplies are good options for reasonable prices. Last, but not least, is the RAM. The latest motherboards implement the dual-channel technology and this means you'd better buy two identical memory sticks for improved performance.   Since all the latest CPUs are based on 400Mhz FSB or more you should buy some DDR400 / PC3200 memory sticks. You can never go wrong with OCZ, Corsair or Mushkin. Supposing your computer is up and running, let's go over the basics of ..

• CPU: AMD XP 1800+ TBred B0 @ 1.5V Default
• Motherboard: ASUS A7N8X Deluxe Revision 2.0 + 1005 Bios
• Memory: KINGMAX 2x256MB DDR333 CL2.5 [dual channel]

As you probably already know, this is the formula for calculating the CPU Frequency: CPU CLOCK x MULTIPLIER. Mine is 133 x 11.5 = 1530Mhz [Xp1800+]. Overclocking can be done nowadays using the BIOS Features. The most important things to have in mind before you go raising your cpu speed are:

• If something goes wrong, don't panic.
• ALWAYS increase the values in SMALL steps.
• At High FSB Values and Frequencies for the RAM and CPU you need to increase the voltage. DO NOT set the highest values from the beginning. It may be unnecessary and it may damage your components.
• If your computer does not POST (Boot), the selected values may be inappropriate. Clear the CMOS (using the jumper located on your motherboard), go back to BIOS and use lower settings. Be sure to consult the Manual that came along with your board to see the location of the jumper.
• If you can't start your computer, don't RMA your motherboard immediately. There is still hope. Use our forums and we'll be sure you get all the help you need.

• Increasing ONLY the Multiplier
• Increasing ONLY the CPU Clock [FSB].
• Increasing BOTH the Multiplier and the FSB. Since this is the most common method because you can achieve certain values in different ways, I am going to exemplify how to get from Xp1800+ to Xp2800+ or higher just poking with these two settings.

For my Xp1800+ the first thing I tried was finding out the maximum value for my Multiplier since my CPU is locked. As expected, it is 12.5, so that would give me 133 * 12.5 = Xp2000+. Next I set my CPU Clock at 166, since my Memory Sticks are DDR333 I thought they would run at 333Mhz without problems. Unfortunately they run at these specifications only with 2.8V (I increased my VDimm with 0.2V). I also had to set my VCore from 1.5V to 1.525V to have a rock stable sistem. 166 * 12.5 = Xp2600+. I've just obtainded 550 Mhz easily. I know I am limited by my RAM therefore I had to know what is the maximum value I can reach. It turned out to be 2363Mhz, that being 189*12.5. So, overall, I have gained a plus of 833Mhz. And believe me, this is quite a lot with ordinary cooling and a limitation of 1.75VCore.

To see how far you can go, you should try small changes. I tried 166, 170, 175, 180, 182, 184, 185 and so on, up to 189. At 190 I couldn't get my OS loaded. Keep in mind that when you increase your CPU Speed and the FSB gets higher and higher, your Memory could crash even if you raise the VDimm as well. In this cases you have to change the Memory Timings accordingly. I finally set at 180*12.5 = Xp2800+. I consider this to be enough without stressing any of my components. The VCore is set to 1.65V and the VDimm is set to 2.8V. Note: If your chipset does NOT support the feature of blocking the Frequencies of the AGP and PCI slots then you may encounter problems at higher FSB Values. Remember that the normally, the AGP runs at 50% of the FSB Speed and the PCI runs at 50% of the AGP Speed: FSB/AGP/PCI = 1/2/4. So if you set your FSB to 400 (200x2), and do not lock the AGP and PCI they would run at ~ 100 Mhz and ~ 50 Mhz which aren't really safe values. It is your own risk to assume. Of course there are various settings to avoid this, but the downside of this is that it lowers the FSB Value. The most common example is 4/3: FSB = CPU CLOCK * 4 / 3. This means that if you set your CPU Clock to 166 and use this 4/3 ratio, the FSB will be only 250 (2x125) instead of 333. As mentioned, the new models of motherboards can lock the AGP/PCI frequencies with no connection to the FSB or offer different ratios to suite your needs. There are not universal values. It all resides in testing this values on your system until it becomes stable at higher speeds.

After you manage to set your computer at some high speed it is time to tweak the memory timings until you have the best ones. This is done only by intensive testing with programs like SiSoft Sandra or different games that need a lot of bandwidth (Quake3 is a good example). I found out that for my CL2.5 Modules the best values are 8-3-3-2.5. The first value [8] is the SDRAM Active Precharge Delay, the second [3] is the SDRAM RAS to CAS Delay and the third [3] is the SDRAM RAS Precharge Delay. The last value [2.5] is the CAS Latency of your Memory Modules. Superior Memory Modules offer the posibility of setting these timings at low values with high FSB Settings. So you should really get some CL2.0 Memory Modules if you want high bandwidth results. At 333 or PC2700 the maximum theoretical bandwidth is 2700MB/s as the name states. With my CL2.5 Memory at 8-3-3-2.5 I've been able to reach ~ 2600MB/s. And I guess that with some 6-2-2-2 timings I would get to those 2700 MBs. For the nForce2 motherboards the lowest timings aren't really the best. I've found out that except for CL2 and CL3 where 5-3-3-2 were the best, at CL2.5 setting my memory at 8-3-3-2.5 gives me more bandwidth then 6-3-3-2.5 which is supposed to be one of the best combinations.

My advice is to run long tests to stress your computer just to be sure your configuration is stable. There are several programs for this: Prime95, SuperPI, The Burn-In test from SiSoft Sandra, Mem-Test and so on. If your computer hangs or reboots this means that you have to go over the settings and lower them, because it's most likely your computer will crash at certain times. When you have ran all those tests and everything is ok, you should settle with those values and consider you have overclocked your system the best you could have.

Now you know almost everything there is to know about basic overclocking. I have included some images from my BIOS to better see these values I've been talking about. Please post your questions and opinions in the forums. We would really like to get some feedback from our readers.