We used the overclocking settings of our Asus motherboard and we set overclocking to 1000FSB/667RAM for the Intel Pentium 4 3.00Ghz 530. The CPU launched at 3.75Ghz.

In the case of the Intel 660, we discovered a bug on our motherboard. If we set overclocking to automatic settings, even if we set it to 30%, the CPU couldn't manage to go over 3.65Ghz. This is because the multiplier was decreased automatically from 18 to 14, although we had disabled the appropriate feature for this ( CPU Lock Free) and set the maximum for the multiplier. In this case, we manually changed the FSB. As it can been seen below, the 3.6Ghz CPU reached almost 4.00Ghz. We believe that the CPU could perform even higher than this.

The CPU temperature at idle was approximately 40 °C. When we overclocked the CPU to 4.00Ghz, this changed to 44 °C.

We also ran an Arithmetic Benchmark from SiSoft Sandra 2005 which produced these results:

We have seen higher core speeds for both of the two CPU's, for example the P4 530 from 3.00Ghz to 3.9Ghz but with a different system, motherboard, RAM, chipsets, etc. Unfortunately, during our tests, we couldn't overclock any higher and it wouldn't be fair to report performances for these two CPUs on different systems.