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Overclocking Guide

Selecting a Processor

If you already own a Pentium III, then you can probably skip past this section - unless of course you're interested in upgrading to a more overclocking processor. The following processors have been overclocked with good results for a lot of folks, including in our test labs. The two biggest classes of Pentium III you want to focus on are the 'E' and 'EB' varieties - since they offer 256KB of on-die L2 cache, while the 'B' has 512KB of off-die L2 cache. I also recommend picking up the boxed, retail versions over the OEM versions (the warranty is better, as is the quality in general).

·  Pentium III 566MHz

·  Pentium III 600 & 650MHz (stepping cb0)

·  Pentium III 733MHz

The 600 and 650MHz Pentium III's (the 'E' models) have a VERY high chance of being overclocked up to 133MHz bus speed. This yields 800MHz and 865MHz respectively - a fairly healthy increase in clock speed.

As general rules of them, however, you can expect the following increases in overall clock speeds beyond the stock rated speed:

·  Common P3 Socket370 FC-PGA Overclocks: 100 to 150MHz

·  Less Common P3 Socket370 FC-PGA Overclocks: 150 to 250MHz

·  Rare P3 Socket370 FC-PGA Overclocks: 250 to 400MHz

·  Extremely Rare P3 Socket370 FC-PGA Overclocks: 400MHz+

Heat Is The Enemy

When overclocking your processor, the biggest issue that will prevent it from running at higher core frequencies is heat. By increasing the FSB speed, and perhaps the core voltage as well, you're not only increasing the core frequency of the processor - you're also increasing the amount of heat that the processor is generating. So, you're going to want to take some steps before you consider overclocking your processor to ensure that it can reach it's optimal speed and still remain fairly cool.

Iwill's Slocket-II

The first step to undertake is to make sure your case has good airflow. The best way to do this is to have both intake and exhaust case fans installed, at the front and rear of your rig respectively. Depending on your case size, you can install fans of varying size and power. At the least, you should have one intake fan and one exhaust fan to ensure that airflow is good. Some cases can handle two fans in front, and two in back - which is a fairly optimal solution. Case fans are available from your local Radio Shack or other electronic store, and from online merchants. Sizes range from 60mm all the way up to the gargantuan 120mm models - so make sure to order one that fits your particular case.

Heatsink/Fan Guidelines:

The next step, and a critical one at that, is choosing the proper heatsink/fan combo. This will be attached to your processor to take heat away from it, allowing it to dissipate on the fins of the heatsink. This is one particular area where you don't want to skimp on - going cheap here can hurt the maximum overclock you'll be able to achieve. I recommend a few particular models, both for active heatsinks and passive.

For passive models, check out what Alpha has to offer. These are some of the highest quality heatsinks around, and have a proven track record. For FC-PGA Coppermine chips I primarily recommend the Alpha PAL35t - which should run you in the neighborhood of $35 - $40. Another recommended brand is Globalwin, particularly their FOP32 unit, which is a cheap $25. In the exotic department, Azzo.com is offering the Hedgehog, a copper-based heatsink which can offer better heat transfer properties than even the Alpha - but at a $45 cost.

In the active cooling department, I recommend the Swiftech MC370-3 Active Peltier Cooler, which I recently took an in-depth look at. We've had incredible experiences with this particular unit, taking chips to new overclocking heights that were unseen with passive cooling solutions. There are other, more exotic, forms of active cooling such as water-cooling systems and liquid-nitrogen cooled setups, but I don't consider these options to the average overclocking enthusiast, which is why they are not discussed here.

When you're installing your heatsink, you should have gotten a tube of thermal tape or thermal paste (better). This goes in between the underside of the heatsink and the top of the exposed portion of the CPU. It smooth out the bumps and inconsistencies in both, and ensures good heat transfer from the CPU to the heatsink.

An Installed Swiftech MC370-3 Peltier

And last but not least, don't forget to try running your machine topless, as in with the case panels removed. For a lot of cases this increases the airflow, and keeps nice cool air around the processor - a benefit when trying to overclock. Don't be afraid of having the panels off - all of the cool kids are doing it, and you'll be best friends with them if you do. Er, actually, it's perfectly safe to have the panels off, just be careful when close to the machine, and possibly wipe out the dust every month or two. It's a bit of a misconception that people have, but there isn't a noticeable difference in dust build up with and without the case covers on. If you have the covers on, the fans suck in dust particles as it is. With the panels off, the dust from the outside can settle among the case, but some of the dust sucked through the fans passes into the air outside and settles elsewhere. Either way you've got dust in your machine, so try and keep it nice and clean for when company stops by.

Other Concerns

With the processor concerns taken care of, I still need to talk about both memory and mainboard concerns. You might already have a mainboard that has overclocking options such as FSB and core voltage tweaks, but if you're upgrading from an older system the chances are slim. In this case, we're happy to let you know that almost all of the popular after-market mainboards have overclocking options standard at this point. However, some stand out from the crowd as being quite exceptional.

If you're going to be purchasing a legacy 440BX chipset based board, keep the MSI BXMaster at the top of your list. This is possibly THE best 440BX board ever produced, as it includes tons of options, a dizzying array of FSB speeds to choose from, and even comes with ATA/66 support. The 440BX chipset is over three years old at this point, but can still support 'E' type Coppermine processors. For those into performance numbers, this chipset outperforms even the latest from Intel, the i815 chipset in almost every application. This chipset was originally designed at 100MHz (and PC-100 memory), but has no problems running chips up to and beyond the 133MHz mark.

If you opt to go this route, you'll also have to get a Slocket-II adapter card. This allows you to utilize FC-PGA chips, which have 370 pins, in Slot1-based boards. This is a relatively small cost, but something to consider none-the-less. We've tested the Iwill Slocket-II adapter and found it quite acceptable during our overclocking tests.

However, the i815 is brand new and offers official support for PC-133 memory, as well as support for 'EB' type Coppermine processors in their socketed form. If you need to be swayed that i815 is a better investment than 440BX, please read our review of the Asus CUSL2, which is the best i815 based mainboard available. The difference in performance between the i815 and the 440BX chipsets is small, and I feel that the feature set of i815 outweighs this minute performance difference.

Memory

Because you're going to be increasing the FSB speed, you'll also be increasing the speed at which your RAM runs at. For this reason, you'll want to stick to purchasing PC-133 RAM or better. For optimal performance, I recommend HSDRAM from Enhanced Memory Systems[http://www.pc133memory.com], which we've taken up to the 160MHz level.

If you're looking to cut costs, you can opt for generic, and cheap, PC-133 RAM. If you're not planning on overclocking above 133MHz you should be fine. But, if you plan on running your FSB higher you'll be better off with a higher quality product, such as what Enhanced Memory Systems offers.

If you are going to be using a 440BX based board, the memory and FSB speeds are ties together. Meaning that the speed at which the memory operates is derived from what the FSB is set to. On i815-based boards, and those that employ the VIA Apollo 133 chipset, the memory speed is independent of the FSB speed. This allows the user to tweak each independently of the other, maximizing stability for each.

Overclocking Technique

Now that I have all of the bases covered in terms of what hardware you should be using, I can dive into the actual overclocking procedure. First off, I recommend removing all of the non-necessary components from the system. This would include everything but your video card, primary hard disk, floppy drive, and CD-ROM unit.

This is because the bus speeds that your peripheral cards run at are derived, in part, from the FSB speed - particularly in 440BX based mainboards. By removing these devices, you can cut down on your troubleshooting woes once you begin to push your processor to its limits.

Now you're set to start pushing your CPU. Boot up the system, and enter the BIOS. This is generally done by pressing the 'delete' key, but could be another key depending on the particular BIOS your mainboard is equipped with. Exactly which key to press is displayed in the lower left hand corner of the boot screen. Once you get into the BIOS, it should look something like this:

An Initial BIOS Screen

This next part varies on a motherboard to motherboard basis, so I will only touch on the generic steps. The specific methodology should be outlined by the user manual for your mainboard. Armed with that, and this guide, you should be set to go.

Overclocking Technique Continued

From the main BIOS menu, there should be a section that is specifically for all of the overclocking options. In Abit boards it is called 'Soft Menu', while in MSI boards it is called 'CPU Plug & Play'. In any case, you're looking primarily for the ability to adjust the FSB speed and core voltage. In order to specify the FSB, the BIOS will generally require you to set the multiplier as well, which you should be able to do by dividing the default processor speed by the default bus speed (600MHz / 100MHz = 6.0).

The Overclocking Section Of An MSI BXMaster

With this parameter set, you should then be able to adjust the FSB and voltage as you see fit. You'll want to take baby steps at first until you know if you're CPU is a strong overclocker or weak. The BIOS should have the default voltage set for your processor, which you may want to bump up a bit while you're testing. If, for instance, the voltage was set for 1.7v stock, you would want to bump it up to 1.75v or 1.80v while testing the CPU. This will maximize the CPU's stability, helping to eliminate another troubleshooting woe.

While you're testing you might also want to set your SDRAM timings for their slowest possible values, though these options are generally in a different area of the BIOS than the FSB/core voltage tweaking section. Consult your motherboard documentation for their location, or simply peruse the various menu screens until you've found them. Typically, you'll want your SDRAM's CAS timing rating to be no lower than 3-3-3, which is the SDRAM's most stable mode.

To get an idea of how good of an overclocking candidate you're CPU is, you'll want to steadily increase the FSB until the machine locks up during the boot phase. To do this, set a given FSB speed, and reboot into Windows. When the boot phase for Windows starts to lockup, or the machine refuses to turn on you've gone too far and you'll have to back off the FSB a bit.

Overclocking Technique Continued

If you lock the machine up, there is a jumper on the board that clears the BIOS back to it's default state. Consult your documentation for the location of this jumper, and place the jumper over the prescribed terminals. When you power on the machine, nothing should happen. Now place the jumper back to its original state - and the machine should boot up. At this point, you can go back to adjusting the FSB setting, albeit at a lower value than what you previously tried.

The best advice that I can offer here is to have patience, and do a lot of testing. It takes awhile to find a good, stable, FSB that your system is happy running at. Once you've found it, you'll want to stress the CPU with some applications. I recommend doing some runs of Q3:A for an hour or two, followed by running the Prime95 torture test. This test generates prime numbers, and tends to weed out unstable settings for the CPU because it requires intense calculations that tend to stress the CPU and generate plenty of heat. If the machine locks up during any part of what I call the 'burn in' process, you're going to have to back off the FSB setting or increase the core voltage in order to gain stability.

Once you've found a good, stable, FSB setting its time to start backing the voltage back down as close to the default as possible. Your particular chip may require a good bit of additional voltage to maintain stability, or it might not - it all depends on the particular CPU you have. The reason for decreasing the voltage is to minimize power consumption, which in tern keeps heat at a minimum, and can help keep your overclocked chip running longer.

Conclusion

The Pentium III is one of the strongest overclocking CPU lines on the market. Many of its available speed grades can be overclocked quite significantly with relative ease. The best news is that because Intel has been manufacturing these chips for almost 2 years, the quality of the chips across the board is fairly good. This means that the chances of getting a good overclocking CPU candidate are fairly high, though there are still 'lemons' to be had.

If you're interested in getting a CPU guaranteed of overclocking well, several online merchants sell chips which have been tested to certain levels ( Outside Loop is one such example). These merchants do charge a premium price for these chips, but the chips also come with a warranty of at least a year - guaranteeing operation at the overclocked frequency. For some, this is a better solution than gambling and purchasing a random retail or OEM Pentium III.

In any case, you should have plenty of instructions and confidence to take your Pentium III to new heights. As I have stressed throughout this guide, some CPUs overclock better than others - so expect your results to vary widely as compared with those on the 'Net and with friends. Overclocking can be a fun activity, provided you have patience and don't mind locking up your computer while your testing.

© 2004 by Lam Ri Hui. All rights reserved.