i7-4820k suppose to only turbo boost 1 core?

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#1 Posted by DJP3000 (293 posts) -

I recently got a good deal on an i7-4820k so I purchased one.  I'm not sure if my motherboard's BIOS can correctly detect the default turbo settings for my 4820k.  The latest BIOS for my board says that it support Ivybridge-E.  My motherboard is an Asus P9X79 Pro with BIOS version 4302.  It seems that I only get turbo when 1 core is active.  When more than one core is active then there is no turbo boost as CPU-z shows 3.7GHz.  I checked the Intel Turbo Frequency Table and it says that the 4820k's turbo bins above base clock from 2-4 cores is 0 and 2 for only 1 core, but then the table shows that it's 3.6GHz when 2-4 cores and 3.8Ghz on 1 core.  The 2nd part that shows the turbo frequencies for this chip says different from what is advertised for this chip as it's advertised to turbo up to 3.9GHz and that's what it defaults to on my chip when only 1 core is active.  Anyone here with a 4820k on a different motherboard get no turbo when using more than 1 core when running at stock settings without multicore enhancement?  Is the turbo boost running as it suppose to on my chip?  I don't think my chip is defective because a few weeks ago I purchased a 4820k and it showed the same turbo behavior but I returned it because it was unstable.

#2 Posted by C_Rule (9739 posts) -
Disregard turbo and just overclock it.
#3 Posted by DJP3000 (293 posts) -

I don't normally overclock my hardware.  I also just bought the chip today and want to make sure it's stable at stock settings before I even consider overclocking it.  I also just wanted to know if my chip is turboing the way it suppose to at stock settings because if my motherboard's BIOS is not auto detecting the correct turbo clocks on my chip then I can just manually enter them in the BIOS if I know what the stock turbo settings are for my chip?  

#4 Posted by FaustArp (1038 posts) -

Go into the Windows Control Panel and set the power-saving option to "prefer maximum performance" and see if that helps.

#5 Posted by DJP3000 (293 posts) -

It's set to high performance and min CPU speed is set to 100%.  Maybe a resinstall of Windows 7?  I just find it weird that only if 1 core is active then turbo boost gets activated and goes up 2 bins.  In the past with other i7 CPU's I owned the turbo boost would still kick in when all cores are active but on this one it's only when 1 core is active.  Also my 4820k is well within thermal limits during CPU stress tests.  The hottest core temperature was 57c during Prime 95. I also wonder if a CPU bound game that uses only 2 cores but not consistantly would cause stuttering because of the fluctuating turbo boost from 3.9GHz-3.7GHz-3.9GHz-3.7GH-3.9GHz when swtiching between 1 core active to 2 cores active back to back.  Is that possible?

#6 Posted by DJP3000 (293 posts) -

Is there any reason why I should not just synch all cores to turbo boot to 3.9GHz on my i7-4820k since there is only turbo boost when 1 core is active if I set the turbo boost core settings to Per Core and Auto.  My motherboards synchs all the cores of my 4820k to turbo boost to 3.9GHz if the memory setting is something different than Auto. I set my memory to XMP and just let it synch all cores to turbo to 3.9GHz but is there any that I should not let it synch all cores to the top turbo boost clock?  Also when all cores are set to synch to turbo boost 3.9GHz (top stock turbo clock for my CPU), the vcore is 1.160v during idle and 1.144v during full load. Is 1.160v a safe vcore for the  i7-4820k if it's running at top stock turbo clocks on all cores?  I did not touch the vcore settings. I also turned off C-states. I have an Asus P9X79 Pro motherboard with the current BIOS version.