January 22, 1999 Web posted at: 11:45 AM EST by George Chronis

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(IDG) -- Gamers are easy to peg. Give us fast, give us high quality, give us reliability—and give it to us really cheap. In the world of CPUs, AMD gave gamers what they wanted in the K6-2. AMD’s threat to Intel is real: the computer sales demographic that’s expanding the most is the sub-$1,000 category. In response, Intel took its Pentium II design, stripped away frills such as the Level 2 (L2) cache that speeds CPU processing and the console-like CPU cartridge, and created the Celeron. And while Intel’s original cacheless Celeron was routinely vilified, it did have one strong suit: it loved to be overclocked to a much higher speed—unlike the Pentium II, whose L2 cache balked if you tried.

Overclocking?

Every CPU has a recommended clock speed—those three digits that appear before “MHz” in the sales literature. The faster the clock speed in a given CPU family, the faster the processing speed. But chip designers usually build in some performance overhead. Since a CPU family usually shares many features, a 266MHz Pentium II has a lot in common with a 333MHz Pentium II.

Speed and power have drawbacks—namely more heat output and power requirements. When you buy the officially faster CPU, those considerations have been taken into account so that reliability isn’t a big issue. But for gamers who are fearless and don’t mind voiding their warranty, a motherboard can be set to run slower CPUs at a faster clock speed.

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If you’re lucky, the slower CPU has enough extra performance headroom not to be bothered by the faster settings. At worst, long hours of use running at temperatures much higher than intended can literally cause the CPU to burn itself out within a year. But in the interest of answering the many questions we get from our readers about overclocking, we decided it was time to give it a try.

Give me an "A"

Intel recently redesigned the Celeron to include an on-chip 128K of L2 cache and released two new CPUs, the 300A and the 333. What’s more, these new Celerons are cut from the same 100MHz, 25-micron cloth as the latest 400MHz Pentium IIs—smaller, less power hungry, more efficient.

The difference between the Celeron’s cache and a Pentium II’s is that the Celeron has its cache completely integrated within the CPU, where a standard PII has it in a separate module. The Celeron’s cache also runs at the same speed as the processor, where a Pentium II’s is uniformly slower than the CPU. Because of that tighter integration, the new Celerons are still more amiable to overclocking. We decided to build and test a Celeron system overclocked from 300MHz to 450MHz.

Because overclocking is accomplished by multiplying an existing CPU speed, and because Intel often builds in limits to these multipliers, it’s sometimes best to work with a slower CPU because you have a larger set of multipliers. That’s the case with the 300A. The 300MHz chip is easy to punch to 350MHz, 400MHz, or 450MHz. To get 450MHz on a 100MHz motherboard, the multiplier is 4.5.

Necessary gear

Building an overclocked PC is practically the same process as building a regular PC, but there are two additional considerations that must be addressed—heat and easy access to jumper settings.

As mentioned above, overclocked CPUs can run very hot, so you’ll want to take every precaution to keep them cool. If you buy a boxed 300A, it may very well come with a heat sink already attached. That’s why we went with a $130 (compared to $600 for a 450MHz Pentium II chip) non-boxed OEM 300A and purchased a heavy-duty Celeron heat sink/fan unit separately. Another consideration is your PC case. Most ATX cases have a fan mounted right above the CPU area on the motherboard. But some of these case fans pull air through the interior, while others push air directly through the interior right over the CPU. We chose a case that pushed air over the Celeron, thinking it would do more to keep the CPU cool.

As for jumper settings, most motherboards force you to look up in the manual which combination of tiny plastic jumpers need to go in which order for every speed and power configuration. This can get quite tedious. But Abit is a motherboard maker that makes the job easy. The company’s 100MHz BX-6 and BH-6 boards have extra BIOS setup options that allow you to set CPU speed and voltage in software—no fiddling with jumpers necessary. We went with the BH-6 Slot 1 board. It’s newer and cheaper than its sibling and better supports more recent processors.

The results

Construction of our Celeron PC was straightforward. We filled out the box with 64MB of 100MHz SDRAM, a Seagate 8GB Medalist Ultra DMA hard drive, an nVIDIA TNT AGP reference 2D/3D video card, a Monster 3D II Voodoo II accelerator, Sony’s 32x CD-ROM drive, and a Turtle Beach A3DXStream PCI sound card.

Although it took a couple of tries to choose the right voltage setting to match the 450MHz speed we selected in BIOS, the system booted up and ran flawlessly. Win 98 installed perfectly and had no problems with the CPU and our peripherals. Our first test was to bolt the case cover on and let the machine loop Quake II demos for 24 hours to see how hot the CPU got after continuous usage. Opening it up a day later, we were amazed to discover that the CPU was running cool. The big test is whether you can put your finger on the Celeron circuit board without being singed. In this case, the area around the CPU was barely lukewarm.

In over a month, there hasn’t been one heat-related glitch or lockup, and we can find no overclocking related problems with any games or applications installed. Extended usage over many months will tell the real story, but from our experience so far, there are no visible pitfalls. The damn thing just runs—fast!

The fastest PC we had available to test against is Falcon’s $4,500, 450MHz Mach V Pentium II. You can see how the two stacked up in the sidebar on page 134. The Celeron performs close to the upper tier of Pentium II CPUs while saving at least $450 in the process. Remember, Intel does not recommend that you overclock its processors, and you void your warranty if you choose to do so. However, our experience with the 300A has been exceptional.

Systems stats and more

Systems Stats

PC	32-Bit CPU Test	Hard Disk
Celeron 450MHz	921	4,480
Falcon 450MHz Mach V	1,070	12,000
*WinBench 99

Game Frames: Celeron (Canopus Pure3D II LX)

Game	640-by-480	800-by-600
Quake II	60 fps	60 fps
Incoming	58 fps	41 fps
Unreal	45 fps	28 fps