by Bubba "Masterfung" Wolford

Pentium II

Introduced at the 233 MHz speed and .35-micron, the Pentium II "Klamath" (233-300 MHz) were a leap in Floating Point Unit (FPU) Performance over Pentium. Klamath also introduced the Slot 1, which called for new motherboards and shortly after the Pentium II came the Accelerated Graphics Port (AGP) video card slot. The "Deschutes" Intel Pentium II was on a .25-micron and ran at CPU speeds from 333 MHz to 450 MHz.

Unlike the Celeron, the initial Pentium II CPUs carried 512K cache. Another difference between Celeron and Pentium II is that the cache in a Pentium II only runs at half the speed of the CPU. In other words, if you have a Pentium II 400 MHz CPU then you should know that your 512K of cache is running at 200 MHz. A Pentium II 450's cache runs at 225 MHz and so forth…

Of course, Intel released the Pentium II long before Celeron came to the market. One bonus of buying the Pentium II is that it comes with higher clock speeds than Celeron. However, once the 300a Celeron was released and word was spreading about its potential to hit 450 MHz and above, many realized that you could buy a Celeron and hit higher clock speeds for fewer dollars than the Pentium II.

Once Intel realized what was happening, they released the 450 MHz Pentium II CPU. However, those with Celerons clocked to 450 MHz or above were still finding their computers were faster than those with equivalent CPU speed Pentium II's. The reason for this was simple: the cache.

The full speed of the cache in a Windows 95 or Windows 98 environment was pushing the Celeron CPU to more FPS than an equivalent speed Pentium II. Where the Pentium II would handily defeat the Celeron was in a Windows NT environment where having the extra cache would often pay off when running heavy programs such as CAD and graphic applications.

However, just as the Celeron, the Pentium II is overclockable. Reaching a bus speed of 112 MHz (a Pentium II 450 with a bus speed of 112 MHz would clock out to 504 MHz) seems to be no problem for all Pentium II's. Of course, being able to adjust voltage and bus speeds excludes all proprietary computers systems (Dell, Gateway, Packard Hell- er, Bell.. any pre-built system) and often many different motherboards.

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Those familiar with overclocking will also take note that any time voltages are increased, the CPU puts out more heat. Thus when voltages reach 2.10 or higher (never exceed 2.30 volts with any Celeron, Pentium II, or Pentium III CPU, doesn't apply to Klamath P2 processors 300 MHz and below which ran at 2.8v) extra cooling on the CPU and computer case is often required.

Pentium III

Intel's answer to this dilemma was to introduce the Pentium III "Katmai." Actually, "Katmai" provided two solutions for Intel, both of which are found in the difference between Pentium III and Pentium II.

The first difference is encapsulated in a simple acronym: SIMD. SIMD stands for Single Instruction, Multiple Data. Streaming SIMD is seventy 3D accelerated multimedia instructions built onto the CPU similar to 3DNOW!, which was introduced by AMD back in 1998.

The new instructions allow for the CPU to handle some 3D calculations directly on the CPU thus creating more FPS for the games that support SIMD. Just like 3DNOW! and MMX, for a game to support SIMD it must be coded in. As far as I know, no flight simulations currently out support SIMD or 3DNOW!, though SIMIS, Wayward Design and others are coding some support.

One of the features that businesses hear about Pentium III is the Java code that is accelerated by Pentium III. The SIMD instructions also accelerate what we see on the Internet.

Increased Clock Rate

The second difference is the increased CPU speeds. Introduced at 450 MHz, the Pentium III has quickly accelerated to 600 MHz.

Early on, the overclocking potential of the 450 MHz CPU's was tremendous! Right away, I helped two friends build Pentium III 450 MHz CPU's, both of which reached 558 MHz with a stock Intel heatsink and single fan. Each only had to have the stock voltage increased from 2.00 to 2.05. Both CPU's were a tremendous value since the 500 MHz CPU's were running over $700 and the 550 MHz CPU were still weeks from release.

Go to Part III