133 MHz FSB: Perfect For Overclocking
Our overclocking project with the Pentium D 805 starts with a front side bus speed of 133 MHz (533 QDR).
FSB clock speed settings may be applied through the BIOS software. Here's an example from an Asus motherboard.
Using programs from the motherboard vendor, or other tools, you can even change the FSB clock rate while Windows is running. Here's an example of Gigabyte's EasyTune 5 program at work on this task.
The following table provides an overview of some of the mathematically possible CPU clock rates that result from raising the FSB clock rate.
|Pentium D 805 with 20x Multiplier|
|FSB clock||CPU clock|
|133 MHz (Default rate)||2.66 GHz|
|140 MHz||2.80 GHz|
|150 MHz||3.00 GHz|
|160 MHz||3.20 GHz|
|166 MHz||3.33 GHz|
|170 MHz||3.40 GHz|
|180 MHz||3.60 GHz|
|190 MHz||3.80 GHz|
|200 MHz||4.00 GHz|
|205 MHz||4.10 GHz|
|210 MHz (THG clock)||4.20 GHz|
|215 MHz (Maximum boot clock)||4.30 GHz|
At first blush, overclocking such a small and cheap CPU to 4.1 GHz seems impossible. Nevertheless, the numbers don't lie, and if you consider the ancestry of this CPU more carefully, this kind of overclocking becomes easier to understand.