Overclocking Basics Are Basic Math
A processor's clock speed is derived from the system base clock, which is 266 MHz in the case of the Intel FSB1066 bus, multiplied by a so-called clock multiplier. The Core 2 Duo E6300 runs at 1,866 MHz (1.86 GHz), which it reaches by multiplying 266 MHz by 7. It would be just perfect to select a higher core clock speed by increasing the multiplier, but unfortunately the CPU manufacturers lock the multiplier at the default value.
Here is a simple example that should work on many P965 enthusiast motherboards:
| Overclocking Example | Core 2 Duo E6300 | ... overclocked |
|---|---|---|
| Front Side Bus | 266 MHz (FSB1066) | 425 MHz (FSB1700) |
| Multiplier | X7 | X7 |
| Core Clock Speed | 1,866 MHz | 2,975 MHz2 |
| Memory Ratio | 2:3(400 MHz FSB to 400 MHz RAM) | 1:11(425 MHz FSB to 425 MHz RAM) |
| Memory Speed | DDR2-800 | DDR2-850 |
- We had to reduce the memory ratio, because the DDR2 speed would have reached 637.5 MHz or DDR2-1275, which is too much for most memory available today.
- You might have to increase CPU core voltage to reach 2.5+ GHz.
In this example we overclocked the Core 2 Duo E6300 from 1.86 GHz to 2.975 GHz. We increased the core voltage from 1.15 V to 1.40 V.
Watch out: even at the 1:1 memory ratio, the DDR2 RAM clocks at 425 MHz (DDR2-850).
For more information on overclocking please check out our article series on overclocking:
