Intel Turbo Mode Technology

As we covered in the BIOS Optimization Guide, the Intel Turbo Mode Technology is an Intel Core i7- and Core i5-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 two or more active threads, the Intel Core i7 Extreme Edition processor will automatically ramp up its processing cores by one bin (133 MHz). When only one thread is active though, the Core i7 Extreme Edition processor will ramp up the sole active processing core by two bins (266 MHz).

The two bin limit can be circumvented in the Core i7-975 Extreme Edition processor. Because it has unlocked multipliers, the Core i7-975 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. Any inactive cores will idle (while remaining at the full clock speed) to reduce thermal output.

DDR3 Memory Controller

The Intel Core i7-975 Extreme Edition processor comes with an integrated DDR3 memory controller that supports memory speeds of DDR3-800 and DDR3-1066. The memory controller will also work with DDR3-1333 memory, albeit unofficially. It also supports three memory channels. This allows the Core i7-975 processor to deliver a peak memory bandwidth of 64 GB/s using DDR3-1333 memory.

However, the Core i7-975's memory controller only rated to support a maximum voltage of 1.575 V, with an unofficial absolute limit of 1.65 V. Going above the absolute limit 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 i7-975. 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.

Support Tech ARP!

If you like our work, you can help support out work by visiting our sponsors, participate in the Tech ARP Forums, or even donate to our fund. Any help you can render is greatly appreciated!