Intel Turbo Mode Technology

As we covered in the BIOS Optimization Guide, the Intel Turbo Mode Technology is an Intel Core i7-specific feature. It is similar to the Intel Dynamic Acceleration feature that was introduced in the 4th-generation Intel Centrino Duo (Santa Rosa) mobile platform. However, there are some fundamental differences in the way it works.

When there are only two active threads, the Intel Core i7 will automatically ramp up two of its processing cores by one bin (133 MHz). When only one thread is active though, the Core i7 will ramp up the sole active processing core by two bins (266 MHz). If there are three or more threads, the Core i7 processor will not overclock any of its processing cores.

The two bin limit can be circumvented in the Core i7-965 Extreme Edition processor. Because it has unlocked multipliers, the Core i7-965 processor can be set to "overclock" its processing cores to much higher clock speeds when there are only 1-2 threads running.

To even out the thermal output, the four cores will automatically rotate being the "active overclocked cores" when Intel Turbo Mode is active. The other 2-3 inactive cores will idle (while remaining at the full clock speed) to reduce thermal output.

DDR3 Memory

The Intel Core i7-965 Extreme Edition processor comes with an integrated DDR3 memory controller that supports memory speeds of DDR3-800, DDR3-1066 and DDR3-1333. It also supports three memory channels. This allows the Core i7-965 processor to deliver a peak memory bandwidth of 64 GB/s using DDR3-1333 memory.

However, the Core i7-965's memory controller only rated to support a maximum voltage of 1.65 V. This is the absolute limit. Going above that will very likely "fry" the memory controller and turn this extremely expensive processor into a piece of useless paperweight.

There is actually no real need to overclock the DDR3 memory modules with the Core i7-965. Its triple memory channels, on-die memory controller and multi-level caches deliver such high memory bandwidth that there is very little performance benefit from using even higher-speed memory modules. Take a look at our article, the Intel Core i7 Memory Bandwidth, and you will see why