PC Processors

[buffalo_bob]

I just installed a new Ryzen 9 3900x and the bios shows all 12 cores are active, but windows only sees 4 cores and 8 "logical processes". Can anyone help?

I've attached a screenshot of my performance task manager screen.

[elstaci · Accepted solution]

Install Ryzen Master and see if it shows all cores active. If not see if you can enable all the cores using the software.

In Windows Search type in and go to MSCONFIG > BOOT > ADVANCE OPTIONS  and Click to place a check in the "Number of processors" box > Click the drop-down menu below the box, and select a number. Note that you cannot select a number larger than the number of processor cores present in your computer > Click "OK" twice, and restart the computer

If all that fails than you may have to reinstall Windows again.

[buffalo_bob]

I *think* this means I have all twelves cores active. Can you confirm?

[elstaci]

Your Ryzen Master indicates that both CCD modes are active. Each with 6 cores. Plus all 12 cores are showing with a running frequency. If any cores were disabled it would have indicated that.

Download the Ryzen Master Quick Reference Guide and User Guide which will explain in detail what all the settings means and how they will change the processor when enabled or disabled.

[buffalo_bob]

Will do, thanks!

[hardcoregames_]

there is an easier tool, CPU-Z which can quickly identify a CPU

[buffalo_bob]

I normally use CPU-Z, but it was only showing 8 cores until just now. No idea why, maybe the Ryzen Master helped somehow?

[hardcoregames_]

buffalo_bob wrote:

I normally use CPU-Z, but it was only showing 8 cores until just now. No idea why, maybe the Ryzen Master helped somehow?

That is why I brought up the BIOS update which usually has more CPU tables on it in addition to other bug fixes

[elstaci]

By any chance, did you change MSCONFIG file to show 12 cores under Processors "Number of Processors"?

If you haven't yet done that, change it and restart the computer and see if all 12 cores are showing.

If it makes no difference then go back and uncheck "Number of Processors' again and leave it like that.

Also try and reset your BIOS/UEFI back to factory settings and see if that helps. You can do it by doing a CMOS CLEAR on the motherboard.

Also play around with Windows Power Plans (Balanced and High Performance) and see if more core shows active.

Check to see how cores are showing when the processor is under load. It is possible during idle some cores are parked and not active until needed.

Ryzen Master Guide should explain that.

[hardcoregames_]

check for an updated BIOS for your motherboard

[elstaci]

Oops, did forget that one important suggestion.

[hardcoregames_]

elstaci wrote:

Oops, did forget that one important suggestion.

This is probably the most overlooked problem many AMD users overlook

[elstaci]

True, but even with his current BIOS it should show all cores enabled.

[hardcoregames_]

elstaci wrote:

True, but even with his current BIOS it should show all cores enabled.

I have seen all kinds of bizarre problems. One reason I like the MSI X570, no CPU needed to flash the BIOS

[buffalo_bob]

I downloaded the most recent mobo drivers as soon as the PC started up for the first time after the upgrade.