For Day 13 of this series, we will cover Intel Turbo Boost Technology. This is not like the the old Turbo button that was on many computers back in the 1980s-1990s. Instead, Turbo Boost Technology and the newer Turbo Boost Technology 2.0 are essentially intelligent overclocking of individual cores of a physical processor. Intel has a short animated demo of how it works here.
When the operating system requests the highest processor performance state (P0), individual cores of the processor have their core speed increased temporarily by varying amounts, based on how many cores are busy, the total power usage of the processor, the ambient temperature of the system, etc.
This core speed increase is very helpful for OLTP workloads, especially if they are processor dependent. The amount of the possible speed increase varies according to the model of the processor, with the newer models with Turbo Boost 2.0 typically getting a 400MHz speed boost over the base clock speed.
I really don’t see any possible downside to this. The base clock speed on Intel processors is rated quite conservatively, with lots of thermal headroom. Having various algorithms in place to temporarily increase the clock speed of individual cores poses very little risk of causing any problems, such as overheating or shorter life for the processor.
One free tool you can use to monitor the effect of Turbo Boost in real-time is called TMonitor, which is available from cpuid.com. A screenshot of the tool in action is shown in Figure 1.
Figure 1: TMonitor running while the system is under a load
Figure 2 shows the Core Speed of Core #0 running at 2932MHz (which is the same as 2.93GHz), even though the rated base clock of my Core i7 930 is only 2.8GHz. The Core i7 930 only has the 1st generation Turbo Boost Technology, which is much less aggressive than the newer Turbo Boost Technology 2.0 in the Sandy Bridge processors.
Figure 2: CPU-Z showing Core #0 running above rated speed