AMD was a busy little company at the time Intel was playing around with their Pentium II's and Celerons. In 1998, AMD released the K6-2. The "2" shows that there are some enhancements made onto the proven K6 core, with higher speeds and higher bus speeds. They probably were also taking a page out of the Pentium "2" book. The most notable new feature of the K6-2 was the addition of 3DNow technology. Just as Intel created the MMX instruction set to speed multimedia applications, AMD created 3DNow to act as an additional 21 instructions on top of the MMX instruction set. With software designed to use the 3DNow instructions, multimedia applications get even more boost. Using 3DNow, larger L1 cache, on-die L2 cache and Socket 7 usability, the K6-2 gained ranks in the market without too much trouble. When used with Socket 7 boards that contained L2 cache on board, the integrated L2 cache on the processor made the motherboard cache considered L3 cache.
The K6-3 processor was basically a K6-2 with 256 KB of on-die L2 cache. The chip could compete well with the Pentium II and even Pentium III's of the early variety. In order to eek out the full potential of the processor core, though, AMD fine tuned the limits of the processor, leading the K6-2 and K6-3 to be a bit picky. The split voltage requirements were pretty rigid, and as a result AMD held a list of "approved" boards that could tolerate such fine control over the voltages. Processor cooling was also an important issue with these chips due to the increased heat. In that regard, they were a bit like the Cyrix 6x86MX processors.
Pentium III (1999)
Intel released the Pentium III "Katmai" processor in February of 1999, running at 450 MHz on a 100MHz bus. Katmai introduced the SSE instruction set, which was basically an extension of MMX that again improved the performance on 3D apps designed to use the new ability. Also dubbed MMX2, SSE contained 70 new instructions, with four simultaneous instructions able to be performed simultaneously. This original Pentium III worked off what was a slightly improved P6 core, so the chip was well suited to multimedia applications. The chip saw controversy, though, when Intel decided to include integrated "processor serial number" (PSN) on Katmai. the PSN was designed to be able to be read over a network, even the internet. The idea, as Intel saw it, was to increase the level of security in online transactions. End users saw it differently. They saw it as an invasion of privacy. After taking a hit in the eye from the PR perspective and getting some pressure from their customers, Intel eventually allowed the tag to be turned off in the BIOS. Katmai eventually saw 600 MHz, but Intel quickly moved on to the Coppermine.
In April of 2000, Intel released their Pentium III Coppermine. While Katmai had 512 KB of L2 cache, Coppermine had half that at only 256 KB. But, the cache was located directly on the CPU core rather than on the daughtercard as typified in previous Slot 1 processors. This made the smaller cache an actual non-issue, because performance benefited. Coppermine also took on a 0.18 micron design and the newer Single Edge Contact Cartridge 2 (SECC 2) package. With SECC 2, the surrounding cartridge only covered one side of the package, as opposed to previous slotted processors. What's more, Intel again saw the logic they had when they took Celeron over to Socket 370, so they eventually released versions of Coppermine in socket format. Coppermine also supported the 133 MHz front side bus. Coppermine proved to be a performance chip and it was and still is used by many PCs. Coppermine eventually saw 1+ GHz.