Intel Pentium III 600

The rate of change in the computer industry is amazing, it's an awesome force that makes the market turn, the developers think, and the consumers drool. Just a year ago the market was preparing for the long awaited year end holiday shopping season, Intel and AMD essentially halted any production of newer CPUs until after the holidays as to make the most off their already powerful flagship products. At this point last year Intel was marveling over the power and performance of their Pentium II which had just recently reached speeds of 450MHz with AMD in the background quietly cracking away at the soon to come, Sharptooth (K6-3) processor.

1997 was clearly Intel's year, AMD's competition to the Pentium II was weak and Intel held on to a great percentage of the market share. In 1998 things started to heat up for the boys in blue as AMD started heavy production of the K6-2 and kept up the competition even after Intel went "Celeron-happy7quot; towards the middle of 1998. As much as some people hate AMD, and as much as others hate Intel, the two companies are good for each other. No one is forcing you to buy an AMD processor if you don't want one, and no one is forcing you to buy an Intel processor if you don't want one either. The benefit of the competition can be noticed in the stronger drive to push prices even lower and raise the performance bar even higher.

Originally Intel had not intended to release a 600MHz processor until later in the year, however with information about AMD's forthcoming Athlon causing a stir amongst the boys in blue the roadmap has been accelerated considerably. For the first time in over three years Intel is engaged in a clock for clock battle with their only real competitor in the desktop x86 market, so when AnandTech was given the opportunity to take an in-depth look at Intel's Pentium III 600 we eagerly jumped at the opportunity. What must AMD live up to when the Athlon (K7) finally goes on sale in August? Let's find out...

The Pentium III, like the Pentium II, features 32KB of L1 cache that operates at its core clock speed (in the case of the P3-600, that speed is 600MHz) and an additional 512KB of L2 cache that operates at 1/2 its core clock speed (300MHz for the P3-600). As briefly mentioned before, the Pentium III features a clock locked 6.0x clock multiplier, for you overclockers that means that like all Intel processors manufactured after the release of the first Celeron in 1998 the Pentium III 600 can only recognize a single clock multiplier, 6.0x. Contrary to rumors, mystical beliefs, or whatever you'd like to call them, the Pentium II, Pentium III, and Celeron all use the same technology that make them what we like to call "clock locked" (meaning their clock multiplier cannot be manipulated), that technology, without physically modifying (and potentially damaging) the processor cannot be worked around.

The clock multiplier has always been a function of the CPU, never a function of the motherboard. The only reason one would believe that the clock multiplier was a function of the motherboard would be because before clock locking techniques were implemented processors could essentially use whatever multipliers the motherboard's jumper settings instructed them to use as long as they were physically supported by the CPU. Take the original Pentium 200 for example, it operated at a 66MHz FSB frequency and recognized clock multipliers ranging from 1.5x to 3.0x in 0.5x increments. Clocking a Pentium 200 at 66 x 2.0 would result in a 133MHz clock speed, and such a setting was controlled via the motherboard. The idea of having the processor accept a single clock multiplier regardless of what the motherboard told it to use never crossed the minds of the engineers at Intel. With the rise of remarking (i.e. selling a Pentium II 233 overclocked to 266MHz as a Pentium II 266 without telling the customer) as a very common practice among unscrupulous CPU vendors it was time for a change, which was first introduced with the Celeron 266, the first desktop Intel processor to feature a locked multiplier, specifically, 4.0x.

The 6.0x clock multiplier of the Pentium III 600 does not mean that it cannot accept a FSB frequency greater than the 100MHz specification Intel intended it to be used with. So overclockers are still able to push the Pentium III 600 to levels above 600MHz without worrying about the clock lock. The FSB frequency setting is a function of the motherboard, specifically the clock generator on the board, so the available FSB settings (albeit unofficially supported) will vary from motherboard to motherboard.