A great idea!
F2bnp wrote:Well, the point is to see how a 486 performs, so no Pentium Overdrive. The Cyrix 5x86 also doesn't clock as high AFAIK so it should be pretty equal in performance to a faster clocked AMD 5x86.
You may want to prefer to the comparative charts in the Ultimate 486 Benchmark Comparison. Only the ALU of an X5-160 has an advantage over a Cyrix 5x86-120. If the games you are testing are heavily FPU-based, a Cyrix 5x86-120 is a better choice.
If you are trying to max out the possibility of a 486 with 3D games, I am in agreement with Sliderider, a Cyrix 5x86-120's FPU is about 10 pentium ratings better than an AMD X5-160. A POD83-WB is 3 pentium ratings better than the Cyrix 5x86-120. If you are using a Cyrix 5x86, ensure that you set LSSER to 0, FP_FAST to 1, and BTB to 1, otherwise, you're preformance drops. Refer to Cyrix 5x86 Register Enhancements Revealed for performance improvements and how to enable these bits. LSSER and FP_FAST are probably the most important for this test, but if you can enable BTB, that's another bonus.
Since you are going to use a 40 MHz FSB, did you confirm that this SiS board is not adding an automatic 2/3 FSB-to-PCI bus multiplier? If so, that would drop the PCI bus down to 27 MHz.
I also think a Voodoo3 card is the way to go. The Voodoo3 OpenGL drivers in Windows just work, which is more than I can say for the Matrox Millennium G200 drivers (at least the old Matrox drivers which are required to use a 486 had OpenGL issues, the later Matrox drivers worked fine with OpenGL on socket 5/7's).
Plan your life wisely, you'll be dead before you know it.