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OVERCLOCK CPU & BUS

Advanced users

Finally there is the ideal option - overclocking both the motherboard BUS and the CPU Clock (Multiplier or Ratio).

This method is likely to give the most satisfactory result combined with the least risk.

The combination can turn a dull system into a Ferrari.

Overclocking BOTH BUS & CPU

It is assumed you have read, and fully understood, the previous two Pages - OC the CPU and OC the BUS

If you have one of the newer motherboards you may safely increase the CPU by about 10-15% and also increase the bus speed (say 66 to 75MHz), and you will have a system that does 'fly'.

The moderate CPU increase will provide an even less moderate overall performance boost. However, when combined with the increased BUS speed, the overall performance is greatly enhanced. Memory and peripherals are operating at increased speed so the enhanced CPU is not left idle so often.

For example a 166MHz altered safely to just 187MHz, but with the bus speed successively increased from 66MHz to 75MHz, is a great system relative to the original.

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Example 1 of Overclocking both BUS and Clock

The original CPU and motherboard are used.
This shows Pentium 166MHz changed to a 187MHz with a BUS speed change from 66 to 75MHz.
There is little risk of chip overheating.
If peripherals do not complain, and do not overheat, then it is very good. Note the small increase in CPU speed (it is not stressed) combined with the moderately increased BUS speed. FAST!

Original settings: Bus at 66MHz, and Clock at 2½ (66 x 2½=166)

Change the Bus to 75MHz, and leave the Clock at 2½,
creating an operating CPU speed of 187MHz (75 x 2½=187)

• • • ALWAYS USE SUFFICIENT COOLING • • •

Example 2 of Overclocking both BUS and Clock

The original CPU and motherboard are used.
This shows a Pentium changed from 166 to 225MHz.
The system would fly relative to a standard 166MHz; possibly faster than a 250MHz. However the system may freeze, you may lose all your data, and you may damage (fry) the CPU and some peripherals (especially that video card!).
Its a bit risky even with substantial cooling.

Original settings: Bus at 66MHz, and Clock at 2½ (66 x 2½=166)

Change the Bus to 75MHz, and change the Clock to 3,
creating an operating CPU speed of 225MHz (75 x 3=225)

• • • ALWAYS USE SUFFICIENT COOLING • • •

Examples of BUS & CPU for PENTIUMs

These examples of PENTIUM overclocking are reputed to have been successful:

  P75MHz - try 90MHz (60x1½)   or   100MHz (66x1½)
P133MHz - try 150MHz (75x2)   or   166MHz (83x2)
P150MHz - its really a P166 MHz so treat it like one
P166MHz - Classic & MMX - try 187.5MHz (75x2½)   or   200MHz (66x3)
P200MHz - Classic & MMX - try 208MHz (83x2½)   or   225MHz (75x3)
P233MHz - MMX - try 250MHz (83x3)   or   266MHz (75x3½)
 

• • • ALWAYS USE SUFFICIENT COOLING • • •

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Links to overclocking Web sites

You will see a fuller list for all Pentium types (including suggestions for many other chip types) at

Tom's Hardware Guide

or
http://www.anandtech.com
http://www.sharkyextreme.com

• • • ALWAYS USE SUFFICIENT COOLING • • •

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Please remember that you alone are responsible for the consequences of any changes you make to your computer hardware or software.

Copyright © LarryM 1998-2015 thpc@mail.com