FSB1066 vs. FSB1333

To analyse the performance differences between the processors with an FSB of 266MHz and those on a 333MHz bus, we compared the Core 2 Duo E6750 and the E6700, which are both clocked at 3.66 GHz.

Our observations from previous articles hold true here as well. The 66 MHz bump to the FSB-speed translates into a slim 1.3% performance advantage under Windows Vista. Since benchmarks always have a certain margin of error, Unreal Tournament and WinRAR actually exhibit slightly lower performance.

In conclusion, we can safely say that the new FSB1333 offers a measurable, though not a tangible performance increase.

We asked ourselves whether processors with different FSB-speeds would also have different power requirements. When they are idle, i.e. when the processors run at lower clockspeeds, there are minor differences. These can be explained by the north bridge’s higher operating frequency on the one hand and the higher CPU frequency on the other hand. Since both use the same minimum multiplier of 6x, an FSB1066 CPU runs at 1.6 GHz, while the FSB1333 CPU runs at 2 GHz when the SpeedStep power-saving feature downclocks the processors.

Under full load, the picture is much the same. After all, both processors are running at the same clock speed.