The Performance Of An Overclocked K6
The K6 is a very overclocking friendly CPU. This reminds me of the time when I ran my AMD 486 DX4/100 at 120 MHz without a problem. The highest speed I could run the K6 233 at was 262.5, which is 3.5 times 75 MHz, but the fastest was 250, 3x83 MHz. I hope the 266 will run at 291 MHz (3.5x83) and this will really kick butt.
The tests were run on the AOpen AP5T, which runs best and most stable at 83 MHz. The DPT PM2144UW ultra wide SCSI controller (where the Cheetah was connected to) was managing the 83 MHz bus speed without the slightest problem.
Windows 95 Hit List
| CPU clock speed/bus speed | Business Winstone 97 |
|---|---|
| K6 250/83 | 58.4 |
| K6 262.5/75 | 57.8 |
| Pentium MMX 250/83 | 56.2 |
| K6 208/83 | 55.2 |
| K6 225/75 | 55.1 |
| K6 233/66 | 54.8 |
| Pentium Pro 233/66 | 54.7 |
| Pentium MMX 208/83 | 53.1 |
| Pentium MMX 225/75 | 52.9 |
| Pentium Pro 200/66 | 52.4 |
| K6 200/66 | 51.9 |
| K6 187.5/75 | 51.9 |
| K6 166/83 | 50.9 |
| Pentium MMX 200 | 50.2 |
| K6 166/66 | 48.6 |
Windows NT Hit List
| CPU clock speed/bus speed | Business Winstone 97 |
|---|---|
| K6 250/83 | 76.3 |
| Pentium Pro 233/66 | 75.8 |
| K6 262.5/75 | 75.1 |
| Pentium MMX 250/83 | 72.8 |
| K6 225/75 | 72.1 |
| K6 208/83 | 71.7 |
| Pentium Pro 200/66 | 71.2 |
| K6 233/66 | 71 |
| Pentium MMX 225/75 | 68.5 |
| Pentium MMX 208/83 | 68.4 |
| K6 200/66 | 67.6 |
| K6 187.5/75 | 67.4 |
| K6 166/83 | 66.5 |
| Pentium MMX 200 | 64.3 |
| K6 166/66 | 63.3 |
You can see that the K6 233 is faster even if you slightly underclock it to 225 MHz. At 250 MHz it's even in Windows NT faster than the Pentium Pro 233 and I guess it's no miracle to my long term visitors, that the K6 166 runs much faster at 2x83=166 MHz.
The most interesting results are the ones of the Pentium Pro. You can see the huge difference between Windows 95 and Windows NT. While it can't beat the K6 233 under Windows 95 it's almost the fastest CPU under NT. This must be important for your decision!! If you are a NT user or if you are planning to become one soon, the Pentium Pro is probably still the best choice, since it's currently also fairly cheap.
