The processors supplied from 2,8V have the least possibilities to change voltages. Unfortunately, among these processors are also processors of Pentium II 233/266/300. The processors that require 2V have the best possibilities to change voltages – Pentium II 333/350/400/450 and Celeron 266/300/300A/333. Their voltages can be changed from 1,8 to 2,6V by isolation of appropriate outputs.
The outputs A121, A120, A119 are on the front, and B120 and B119 – are on the back side of a slot. In total, there are 121 outputs on each side and the first and the last ones are marked as A1 and A121 (B1 and B121). And all odd-numbered outputs (A1, A3, A5, … A121) are on the bottom row and all even-numbered outputs (A2, A4, A6, … A120) are on the top row. To isolate an output, you have only to cover it with lacquer or to stick its wide part.
There are more exotic ways of the hardware overclocking. For example, you may make technological holes in the appropriate places of your processor and add special devices on its diagnostic connector. These devices allow changing the bus frequency and the processor voltage using some switches.