Maximus VI Hero - CPU frequency always at 3800 MHZ

[darkanger4]

Hello guys,
I recently built up a new computer:

Motherboard: Asus Maximus VI Hero; BIOS version 1603
Processor: i7-4790
Memory : HX321C11T2K2/16; Kingston HyperX 16GB DDR3 Kit
• JEDEC: DDR3-1600 CL11-11-11 @1.5V
• XMP Profile #1: DDR3-2133 CL11-12-12 @1.6V
• XMP Profile #2: DDR3-1600 CL9-9-9 @1.6V
Graphic Card: None. I use the one built in the CPU for now.
Monitor: HP LP1965
Storage #1: Samsung 850 Pro 256 GB SSD
Storage #2: Seagate 500GB 7200 HDD
CPU Cooler: CM Hyper 212 EVO
Case: CM HAF 922
Power Supply: CM Silent Pro M700
OS: Windows 7 Ultimate 64 bit

The only setting I made in the BIOS is to set the Memory to XMP profile 1 - XMP Profile #1: DDR3-2133 CL11-12-12 @1.6V. Everything else is on default settings. The Issue here is that my CPU works all the time at 3800 Mhz (x38 multiplier) no matter if the computer stays idle or running Prime95. By specification the CPU should downclock to 3600 Mhz base frequency when idle and go to 4000 Mhz turbo frequency on load (If I understood the Intel specification correctly).
Can you please help me to set the BIOS settings in such way that my CPU stays at 3600 Ghz @ idle and goes to 4000 Ghz on load. I have the latest BIOS version 1603.
This is my first ASUS ROG Mainboard so all the settings in BIOS are new to me and feel kind of lost 😞
Thank you in advance!

[Nate152]

Hello darkanger4 and welcome


The i7 - 4790 is 3.60GHz and boosts to 4.0GHz.

In the bios be sure turbo is enabled in advanced tab, cpu configuration.

If it's enabled, do you by chance have real temp installed?

[PerpetualCycle]

What are your power setting in Windows? If it is "High Performance", your CPU will not downclock. Use "Balanced" power settings.

Also make sure C-states and EIST are enabled in the BIOS.

[darkanger4]

Thanks for the quick replies guys,
PC power plan was indeed set to Samsung High performance, I changed it to Balanced and in BIOS I have C-states, EIST and Turbo mode set to enable.
Now when idle my CPU downclocks to 0.8 GHz and under load goes to 3.8 GHz (Bus speed ~100 MHz and multiplier from 8 to 38). Now my question is how to set the CPU to go to its nominal turbo boost frequency of 4.0 GHz? I have no idea why the max Turbo Frequency goes only to 3.8 GHz.

[Nate152]

Thanks for the screen shots, they do come in handy when troubleshooting a problem such as yours.

With the core ratio on auto it should be boosting to 4.0GHz. I would try disabling the EPU power saving mode, if this doesn't help..

Set the core ratio limit to 40.

[darkanger4]

Thanks for your help Nate152. Much appreciated!
I tried disabling the EPU power saving mode but there was no effect. However I found something weird - when I try to set the core ratio to 40 (or anything higher than 38) it defaults to 38. I am starting to think that this CPU i7 4790 multiplier is locked 200 mhz lower then the advertised turbo frequency. Any other ideas, what I can change next?
Guys, please if anyone has the same CPU share you experience about the max turbo frequency!
Thanks

[Nate152]

I would call intel and tell them your cpu is not boosting to 4.0GHz.

On auto settings it should be boosting to 4.0GHz.

One more thing to check, on the advanced tab, cpu configuration make sure turbo ratio is set to auto, if it is give intel a call.

[darkanger4]

Ok guys thanks for the replies, after some trial and error I found that setting in BIOS - AI Overclock Tuner from XPM to Auto solved the problem. Now my CPU multiplier varies from 8 to 40 and I can see some cores reaching 4.0 GHz from time to time. You can consider this thread as solved.