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The Art of Overclocking
Created on 09 August 2000
Some times ago, an advert from ACD (if I'm not mistaken) openly warned the Mauritian Public that It did not sell Overclocked CPU. Which Somehow meant that Someone, somewhere in Mauritius was doing it. But What exactly is overclocking?

The most important part of your computer is your CPU and the most important selling (and Marketing) aspects of a computer is its SPEED. No need to tell you the recent gluttony from AMD and Intel when the former was the first to reach the Mythical Gigahertz barrier. A CPU (The Brain) works in cycles, that is, data and instructions are carried out one (or more) after the other. Hence a computer with a speed of 1 Megahertz accomplishes 1,000,000 of such cycles. Bear in mind that we are barely touching the very essence of Microprocessors AKA CPU here ! I'm only giving you a crude explanation of it ! So, a Gigahertz PC will accomplish 1000 times more cycles. Ok ! What overclocking does is increase the speed of the CPU FREE... YEP, Free, nadda rupees. How can this be? Let me introduce you to the "speeed bin" concept.

How does Intel and AMD sell their processors?
If you have to buy a PC, the seller will certainly ask you what CPU speed you want. 600, 650, 700, 750 Mhz... Why such speed points? Why not 745 Mhz, 815 Mhz etc? Why (and How) should CPU speed be delivered in increments of 50 Mhz? The "why" part is because of the marketing guy. An array of products for all budgets is better than a single product fitting all budgets. How does Intel and other manufacturers determine their CPU speed? There are 2 answers to that. Firstly in the Fab (where the CPU is manufactured), the CPU comes out batches in Wafer form (a circular piece of Silicon of 12inch to 18inch). Each Wafer has a serial code which identifies it. Then when the final stage of packaging and testing is reached, a randomly selected CPU from each wafer is selected and it will determine the speed of the whole batch. This is a rather simplistic explanation. But let me tell you that some CPU can be underclocked (also..) when too much High-speed CPUs are manufactured (in exceptional cases). The second answer resides on your machine itself. The CPU is plugged in your motherboard (either in Slots, In Slotket or in sockets) and there its speed is determined by the following equation (CPU speed = Front Side Bus Speed x Bus Multiplier). No more details here please. So by tuning the FSB (the bus multiplier has been locked since some times ago by intel and AMD to prevent Mass overclocking), anyone can potentially overclock their CPU. Some CPU are very famous for their overclocking capabilities. The first Cacheless Celeron (Mendocino OR Covington Core - I forgot) were able to reach 400+ Mhz since they did not have the Cache obstacle. But the most famous OVERCLOCKING CPU was the Celeron 300A which in some case underwent 100% overclocking using special features we'll see afterwards. For one year, I used a Celeron 300A overclocked to 450Mhz a full 50% speed increase. I simply changed the FSB from 66 Mhz to 100 Mhz and presto! I had a PC with more power than a PII-450 Mhz (which was top speed at that time).

So now you know how to overclock your CPU... in theory. How do you do it in practice? Unfortunately, I don't have pictures to illustrate, so content yourself with my words only. 

Step 1. Choose your CPU well. Paradoxically, the lower the speed the better the overclocking. Why? Because primo, the lower speed CPu costs less ;), it is less prone to errors that might occur at too high speed and lastly, it is much better to have a Significant percentage increase in FSB than in original bus multiplier since in the first case, the whole system gets a significant boost. You're still with me? Fine... What CPU I shall choose? The newer Pentium 3 500a or 550a (FCPGA socket). They should be damn cheap now ! FSB = 100 Mhz, Multiplier x5 or x5.5. The chipset used doesn't really matter. Intel BX, the newer i815 or VIA chipsets are fine BUT no i810e please!!!

Step 2. Choose the Right motherboard. Some motherboards are my favorites. King of Kings is Asustek followed by Abit, Epox and MSI (Microstar). These motherboards are known for their Overclocker's friendliness and for their stability, very important. But above all, these are not Integrated Mobo (except for sound perhaps..). I'm assuming that you're prepared to use Separated video cards NOT the integrated one, since I sincerely don't like too mcuh the integrated motherboards' overclocking facilities since most of them (matsonic, PC Chips, PC100, Mc Coy, Eurone, Alton etc either automatically determine the Front Side Bus speed or do not allow you to tweak and fine tune your system or simply refuse to boot up on overclocking. So it may be like a lotterY - the Celeron O'clocking was done on a PC CHips board BTW).

Step 3. Choose the right memory (CAS-2 PC133 First parity well known brand, ask your vendor) and the right Video Card (geforce? Riva TNT2 Ultra). NO SIS or Trident or the likes please. Thanks! AHHHHH, the most important thing. VENTILATION. Nothing (except perhaps Salty water.. is more destructive for your PC than Heat) equip yourself with powerful fans. They are pretty cheap and pretty efficient. Opt also for a rather large casing for air circulation.

Step 4. After having collected the right pieces and either assembled them or bought them. Boot your PC. Most (if not all) new motherboard allow you to overclock the CPU right from the bios menu. Aaargh.. No pictures to show you. Anyway when (and if) you enter your bios (delete, f3 keys), go to cpu setting and play over there. ALWAYS set the Motherboard to default setup first before overclocking. Then increase the FSB in small increments (2 Mhz is safe) then reboot and watch out for the CPU speed. Again I shall bear no responsibility in anything that might happen ;) Let your favorite OS launch and then do some casual jobs (play Quake 3 for some minutes, go on the net?) Then repeat the same thing again and again until some thing starts running bad.. Locked at startup for example. In this case, go back to your Bios Menu and VERY carefully increase your Voltage by 1 step at a time. Increasing the Voltage improves overclocking but stresses your CPU more as well... Hence the importance of a good cooler and ventilator. A Pentium 3-550 should reach approximately 135 x 5.5 = 740 Mhz or MUCH more in the range of 800 Mhz. 

Advantages of higher FSB.
When running at higher FSB, the whole system as I told you before, run faster than initially. A bump from 100 Mhz to 133 mhz represents an increase in Memory speed of 33% as well as a similar increase in the Video card speed and the CPU speed. Your system will be definitely under stress MORE but the quality of your components will be crucial in this case. Moreover, you can also try to overclock your video card as well.. But that's a completely difference story now.

Conclusion.
Beware however that overclocking automatically voids your guarantee and diminishes the life expectancy of your CPu. But in today's world, who cares? New CPU's are introduced as to say, every forthnight and this increases artificial obscelency at a rate never seen before. Also Overcloking was never a science (it's more of an art) and as such each overclocking case is unique and might not necessarily repeat itself over and other statistically speaking. Even Great Celeron 300 had 5-10% failure at 450 Mhz ! So good luck with your PC and hope you don't fry your chip.
 

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