Turbo Mode

In short, the turbo boost technology increases the core frequency whenever possible without breaking the TDP limitations set by Intel. Basically, Intel has limited the maximum TDP, or power consumption, to 95W divided over all four cores. So, each core can in theory produce a maximum of 23.75W; that is if we forget about the integrated memory controller other peripherals integrated on the uncore. Each processor is set at a certain stock frequency at which it will not exceed this TDP limitation, even when all four cores are working at full speed.

The problem here is that situations in which all four cores are working at full power at the same time are very rare; in other words, the processor will almost never use all the power it has available. Next to that, there's the fact that any cpu has room to be run at frequencies beyond those set at the Intel labs, as you can see from the many overclocking results. In other words: a lot of room to increase frequency and a lot of room to consume more power. So, what Intel came up with is a dynamic overclocking feature which they call Turbo Mode. It increases the clock frequency of one or two cores if the maximum TDP hasn't been reached in order to make applications that don't fully use the multi-core technology faster anyway.

We used our retail Core i5 750 to check out the performance gain from enabling turbo mode.

No turbo = 20x

4 cores = 21x

3 cores = 22x

2 cores = 23x

1 core = 24x





The MSI P55-GD80 is getting quite a serious hit in the Super PI 32M benchmark; 30 seconds is quite a lot ... the question is if this has to do with memory bandwidth or turbo mode throttling.



Something doesn't quite add up here as the P55-GD80 seems to lose quite a lot of bandwidth when Turbo Mode is turned on. We have checked and double-checked the memory performance, but the same results were obtained every time.



As well as the memory bandwidth, the memory latency takes quite a hit.



In the multi-core benchmark of Cinebench it seems that the GD80 performs better than the UD6.



As we also noticed in the first Core i5 article released here on Madshrimps, there's a performance problem with 3D and enabling Turbo Mode. We are still trying to pinpoint the exact cause of this problem and when we have more data we will fill you in.



The HDD performance takes a serious hit when enabling Turbo Mode.





Notice how in the High preset, where the GPU is stressed more, the performance of a turbo mode configuration falls behind the non-turbo configuration, which is in line with what we see in the PCMark05 benchmark.