11 Replies Latest reply on Oct 1, 2018 2:13 AM by badger3x

    I am not seeing all CPU cores in my A10-7870K


      Howdy folks,

      got an issue in that Windows 8.1 Pro is not seeing all my CPU cores on my A10-7870K.


      Windows thinks I have 1 Core and 2 logical processors.

      (see attached Screenshot 14)


      As far as I know I am on the right BIOS version on my ASUS ROG Crossblade Ranger board.


      CPU-Z is only showing 2 cores and not 4.

      (see attached Screenshot 4 to 13)

      I'm running SightHound security software on the machine to record video streams from my IP cameras, so I want as many cores as possible

      since I am taxing the CPU quite a bit - at times running between 80-95% load - and I am convinced this would be a lot less if it saw all the cores.


      Can someone who knows their way around the Bios a bit better than me see where I have gone wrong??

        • Re: I am not seeing all CPU cores in my A10-7870K

          From Tom's Hardware Thread concern same issue you are having: AMD a10 7860k (4 cores) only using one core? - CPUs


          Copied from above link:


            redgaming110Mar 4, 2018, 9:12 AMI looked in the bios and didn't find anything that tampers with the amount of cores except 'core leveling mode' where it says 'one core per processor, one computer unit and one core per computer unit,' and idea what it means?




            CountMike  Mar 4, 2018, 9:18 AMThat's the reason then. There are 2 cores in one unit and 2 units which would make it 4 cores.
            That's how architecture is in older AMD APUs and FX processors is.
            Reset CMOS/BIOS maybe it gets fixed like that.


          3. From your Asus Support Motherboard Manual: https://dlcdnets.asus.com/pub/ASUS/mb/SocketFM2/Crossblade_Ranger/E9512_Crossblade_Ranger_Guide_web_only.pdf?_ga=2.13394…



            • Re: I am not seeing all CPU cores in my A10-7870K

              Hi elstaci and thanks for your reply.


              If I understand your reference to Toms hardware post correctly, are you implying I am not meant to see all four cores?

              If that is the case, then why does the chap in his post A10-7870k in Dual Graphic with R7 240 in his CPU-Z screenshot (last image in 's post)

              see all four cores? yes different motherboard, but it definitely says he has 4 cores whereas mine only says 2.


              I have adjusted the Bios setting to Enable C6 Mode (the others were set as you recommended already), but it still does not show my

              missing two cores.


              Any further thoughts?

                • Re: I am not seeing all CPU cores in my A10-7870K

                  badger3x, this problem is almost always caused by NOT installing a fresh copy of Windows AFTER the processor is installed.  If this is true in your case, please install a fresh copy and do a Clear CMOS to get your BIOS into a default state.  Good luck and enjoy, John.

                    • Re: I am not seeing all CPU cores in my A10-7870K

                      thank you misterj. You had correctly surmised that I had been lazy and not re-installed. I'll give it a go this weekend and see how I go.

                        • Re: I am not seeing all CPU cores in my A10-7870K

                          I would first reset BIOS to "Default' before reinstalling Windows.


                          Have you tried to activate the APU Cores via Windows itself?


                          Press Windows Key + s (search) from the keyboard->type msconfig->Click on Boot->Advanced Options->Check on Number of Processors->Now select the Processor that you want to activate->Click on Apply->OK."


                          Also run CPU-Z and see how many cores it shows after resetting BIOS to "Default or Optimal Settings" and changing the APU Cores to 4 cores in Windows System Configuration.


                          Then go to Bench in CPU-Z and run both tests for the APU and see what it shows:




                          Normally it is not really necessary to install a clean Windows installation after updating the CPU/APU.


                          But I would do it as a last resort if everything else fails in case Windows OS is corrupted.


                          If I were you, I would do a Windows System Backup of your current Windows installation on a different hard drive by using Windows itself or a 3rd party backup like Easeus or Acronis.


                          That way if by doing a clean Windows install doesn't fix your problem than you can restore your computer using Windows System Backup to get your computer back to the way you had it before.

                          2 of 2 people found this helpful
                            • Re: I am not seeing all CPU cores in my A10-7870K

                              I strongly disagree with elstaci and strongly insist that a fresh install of Windows is needed when processor is changed.  Enjoy, John.

                                • Re: I am not seeing all CPU cores in my A10-7870K

                                  Can you please explain how changing a CPU or APU affects Windows in any way.


                                  Can you link some tech sites that validate what you are implying?


                                  The only thing that will be affected by changing CPU or APUs, in my opinion, is the Motherboard's BIOS. CPUs have no separate drivers to install thus it won't affect Windows. APUs does have drivers for it integrated Graphics. Those can be uninstalled before upgrading the APU to another CPU or APU.


                                  Windows does have some settings that concern CPUs but those can be changed if it affects the new CPU


                                  I have googled " Clean install Windows after CPU upgrade" and all websites basically says about the same thing. It is not necessary to do a clean Windows install for just upgrading the CPU/APU.


                                  If you replace the Motherboard, it is Recommended but not required to do a clean Windows install.


                                  I, myself, upgraded my Phenom II CPU to a FX 8350 CPU without changing Windows (Windows 7). It worked flawlessly without any problems. It booted up and started working correctly. I did go into BIOS and configured a couple of Settings for the new CPU and that was it.


                                  My own opinion on clean installing Windows only when it is corrupted or unusable or upgrading Windows. Otherwise it is a last resort. I have seen many Users mention about installing a Clean Windows and still have the same problems. This is most of the time. Very rarely will doing a clean Windows install actually solve a problem. It can be used to check to see if you have a Hardware or Software problem as a last resort.


                                  But that is my own personal philosophy in troubleshooting concerning installing Windows to fix a problem.


                                  The reason why I am against doing a clean Windows installation besides the reasons giving above, is that many legacy software won't install without using Windows SDK tools to make it possible to install (royal pain to do). Plus it is a long process to reinstall and register all your software and reconfigure Windows and all the software you need to install again.


                                  My suggestion is to do a In-grade Repair which is basically reinstalling the same version of Windows via the Windows Desktop. This will install a good Windows OS again with all your software and personal data intact. It is the same as doing a Windows upgrade on top of the old Windows installed.

                                  1 of 1 people found this helpful
                                    • Re: I am not seeing all CPU cores in my A10-7870K

                                      Thanks, elstaci.  I have no intention of getting into an extensive back and forth on this.  I would like users to make there own informed decision.  I will name three aspects of Windows I think are effected by these types changes: Scheduler, Updates and Drivers.  I think users can choose to correct all three with a fresh install of Windows or take a chance and try to manage the results.  There are many anecdotal accounts of fresh installing/not fresh installing Windows that I believe are not applicable to all users.  After helping many with many different symptoms, I simply recommend a fresh install.  I am fine with any user following your guidance.  Thanks and enjoy, John.

                                        • Re: I am not seeing all CPU cores in my A10-7870K

                                          Last time I will comment on this off-the-thread discussion.


                                          1) Windows drivers are not affected by CPU/APU changes. The APU driver (integrated Graphics) only needs to be uninstalled before installing the new CPU/APU. CPUs  do not have separate CPU Drivers in Windows to install or uninstall.


                                          2) Windows Updates will automatically install any new updates that concerns the new CPU/APU. So that isn't an issue with replacing a CPU/APU. 


                                          3) Windows Scheduler is not going to change by doing a clean install. The same scheduler will be installed again with a clean Windows installation.


                                          4) After installing and upgrading a CPU/APU you may need to upgrade the motherboard BIOS to make it compatible but that isn't related to Windows.


                                          5) Recommending a clean Windows install to fix or prevent problems without thorough troubleshooting, In my opinion,  is like using a Jackhammer to hammer in a small nail instead of using a small hammer first.


                                          Yes, it is best to give the Users all the information they need to make an educated choice on how to troubleshoot their problems. The User is the one that is going to find out if the advice they follow was helpful or harmful.

                                    • Re: I am not seeing all CPU cores in my A10-7870K

                                      Huzzah! I have four processor cores now!!


                                      I can't be 100% sure at time of writing if it was the Bios reset or the clean windows install onto a new SSD.


                                      I started out by looking at my existing installation and poking around in msconfig as elstaci suggested. Not sure what exactly I misclicked in there,

                                      but after a reboot, i had hosed my windows boot disk. yay! It said it needed repair and my USB stick with Win8 install but no dice, it wasnt playing ball.


                                      Subsequently I disconnected this existing SSD with now hosed Win 8.1 boot disk, attached another brand new SSD and used the ASUS prescribed

                                      CMOS reset on the motherboard. Got my Windows 8.0 installed again. Installed CPU Z w.o. having added any other drivers or anything and already it

                                      was seeing all my four cores.


                                      Interestingly having reset default values in the bios interface itself before the CMOS reset did NOT fix my problem.


                                      At this stage I would love to be able to boot from the hosed windows installation again to see if it too now sees four cores and thus confirming the

                                      CMOS reset was what was needed. If I get some time to try and repair it, I will report back.



                                      Thank you all for writing in and helping out.