Intel Turbo Boost Not Working ?

[pmccabe001]

Hi Folks

I'm running ESXI 6.0.0 VMKernel Release Build 3620759 on a Supermicro X10DRi motherboard with 2x Intel Xeon E5-2620 V3 CPUs with base frequency of 2.4 GHz, and Turbo at 3.2 GHz.    

As far as I can tell, I have enabled turbo boost in the BIOS following the instructions for my mother board here:

https://www.supermicro.com/support/faqs/faq.cfm?faq=21555

I have EVC mode disabled and have set the Power Management policy to High Performance.

Running a Windows 7 VM with prime 95 stress test maxing out all 4 cpu cores.

CPU-Z is running, correctly reporting the CPU model.  However the Core Speed never goes above 2.4 GHz.  Also the CPU usage according to the vSphere client is also maxed out at~ 2.5 GHz

Would anybody have any idea as to why I am not seeing the expected 3.2 GHz based on Intel Turbo Boost ?

Thanks so much.

[MattiasN81]

The thing is that almost all Turbo Boost CPUs can't run all cores at the same time at the highest clock frequency due to heat and stability.

The maximum clock (boosted) frequency only applies when one ot two cores are active

The E5-2620v3 has base clock of 2,4Ghz and a All-Core Boost frequency at max 2,6Ghz and a single core clock at 3,2Ghz

We can take the E7-8890 v4 as an example, Intel's latest monster CPU with 24 cores and max clock frequancy at 3,4Ghz.

If the CPU where able to run all cores simultaneously at 3,4Ghz you would actually need to cool the CPU with liquid nitrogen to even keep it alive :smileyhappy:

[pmccabe001]

Interesting, that's good to know.  Thanks