We have now investigated how the K6-III+ processor performs at a variety of clock speeds in a variety of synthetic and gaming-related benchmarking applications. The numbers returned by the various benchmarks deserve final comment:
The synthetic benchmarks stated the obvious: Performance increases as the system clock speed increases. But these showed nearly linear trends, due to testing only one system element, i.e. the processor. Real-world performance is dependent on more factors than raw CPU speed. As both the hybrid and real-world test demonstrated, bus speed is important. 112MHz bus-based processor speeds tended to equal, and in some cases outperform, faster operating speeds based on the slower 100MHz bus. The logical question would then be, why would a "mere" 12MHz make such a difference?
The increase in bus speed breaks down three ways. First, the FSB, which refers to the transfer of data between the chipset Northbridge and the CPU, is increased. In addition to talking with the CPU and memory, the Northbridge also communicates with the PCI bus, the Southbridge, and by extension all system components. Second, data transfer between the Northbridge and the memory has also been increased. Third, the AGP interface to the graphics card is spec'd for 66MHz operation; at 100MHz, this is achieved by using a 2:3 divider. At 112MHz, the system is still using that 2:3 ratio, which means that the AGP interface is running at (2/3) * 112 = 75MHz.
3D games typically require much three-way data transfer between memory, CPU, and video card. Hence, even small bus speed increases can make observable differences in performance. Judging by the data returned in our testing, 112MHz bus-based overclocks are obviously preferable over nearby 100MHz bus-based operating speeds, although on some Super7 motherboards 112MHz bus may not be available. In such cases, 100MHz speeds generally are to be preferred over 95MHz bus or lower, as was demonstrated in my K6-2 article.
The K6-III+ CPU's showing in most benchmarks was stellar if not spectacular, although the Q3A Fast and Fastest results were certainly acceptable for the user who is willing to sacrifice overall image quality for a smoother, cleaner-playing game. The lower scores in MDK2 and MBTR may seem unfortunate, but are to be expected for newer, visually complex games as the CPU simply cannot keep up with the mathematical demands that the software is making. Both games are still playable, albeit not so crisp as a fan of either game might prefer. To summarize, then, the K6-III+ is no barn-burner by modern standards, but for the Super7 user fortunate enough to have one such CPU, it is a reasonably fast solution with just enough horsepower to keep that older machine enjoyable for another year.
For general questions and comments about this article, overclocking, or computer hardware/software in general, stop by the messageboard. For questions specific to this article, feel free to contact me with an email correspondence.
Ace's Hardware - Although Ace's was not cited in this article, Johan De Gelas published an excellent article on the K6-2+, and Jasin Robertson later followed up with a second, briefer review comparing the K6-2+ with other Super7 platforms.
AMD - The place to find information and data sheets for the K6-III+ processor. The 3DNow!-optimized Quake2 patch can be downloaded here.
AnandTech - Although also not cited in the above text, I suggest consulting this review because it examines both the K6-2+ and K6-III+ on a different hardware configuration, and includes several commercial office/productivity benchmarks.
LostCircuits - A hardware-dedicated website with numerous reviews, guides, and "in-your-interest" articles by MS and other LC community members. Check out MS's review of the Shuttle HOT597 board employed in my test setup, and don't miss Roadrunner's comparison of the K6-III and the K6-2. Additionally, MS and Bighammer collaborated to produce a detailed assessment of the K6-III, and page five demonstrates the K6-III's advantage in Winstone testing. Questions about BIOS settings? The LostCircuits BIOS Guide probably has an explanation.
Copyright Notice. All original information and presentation thereof - as well as the presentation of non-original information - contained herein is © 2001 by Aaron Vienot and may not be reprinted without the express permission of the same except in the form of brief quotations for citation purposes, news briefings, or reviews of this article. AMD, Athlon, Duron, K6-2, K6-III, K6-2+, K6-III+, and 3DNow! are trademarks and/or product names belonging to Advanced Micro Devices. Celeron and MMX are trademarks and/or product names belonging to Intel Corp. All other trademarks are the property of their respective owners. CPU-Central has been granted permission to freely reprint this article on the CPU-Central website.