Turbo Boost Technology Basics
Let me briefly remind you what Turbo Boost Technology actually is. All existing Core i7 processors fall within the predefined 130W thermal envelope even under maximum load, when all cores are fully utilized. Of course, when only one core is working, the power consumption will be way lower. However, this core will still work at the same frequency as the other three if the Turbo-mode is disabled. The picture below shows an example of a top Intel Core i7-965 Extreme Edition processor with the 3.2GHz default frequency:
What happens when we enabled Turbo Boost? The Power Control Unit (PCU) integrated into the processors evaluates the situation. If the power consumption and temperature are within the standards, it increases the core frequency to the next step or two steps up. The CPU remains within the 130W TDP, since some cores are idle, the temperature is normal, but the performance increases compared to the same CPU working without the Turbo Boost.
In fact, I believe that Turbo Boost is probably the most important innovation since AMD announced their Cool’n’Quiet processor power-saving technology. Quad-core processors have been selling for a while now, so why don’t we all have quad-core CPUs in our systems yet? Because not everyone needs them. We have to decide if we want to get a quad-core CPU or a dual-core CPU working at higher clock speed. There are quite a few tasks out there that can be split into parallel threads very effectively and a multi-core processor will definitely be faster in them. However, despite this fact, it is still better to have only one or two cores working at higher frequency. Turbo Boost eliminates the need to make this difficult “either this, or that” choice, because it makes any CPU universal. The CPU may work as a multi-core processor employing all computational threads; however, it may as well work as a single-core CPU operating at higher clock speed.
It is important to keep in mind that Turbo Boost may cause some problems during overclocking. Imagine that after a series of experiments you have finally come up with the combination of parameters with which the CPU remains stable under maximum utilization of its al cores. When only one core is utilized, Turbo Boost kicks in and the frequency goes up, which may cause some failures. If the settings choice is based on the maximum frequency we can obtain with enabled Turbo Boost, then our processor cores will work at lower frequency than they could during maximum CPU utilization. Disabling Turbo Boost is also no good, because we will lose all the advantages it has to offer…