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Why my i7 9750H only has six threads while it's supposed to be twelve

yabinda

New Member
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Nov 30, 2020
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I accidentally found that my i7 9750H in Dell Precision 7540 only has six threads. I checked with both cup-z and HWiNFO64 and it indeed has only six threads.

Does anyone know what's the problem here?
 

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unclewebb

ThrottleStop & RealTemp Author
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Jun 1, 2008
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Run msconfig, click on the Boot tab and press the Advanced options... button.
Make sure the Number of processors box is not checked.
Press OK, reboot and maybe Windows will find the rest of your missing CPU.



Edit - You might want to also enable Speed Shift Technology in your BIOS. While you are in there, make sure hyper threading is enabled.
 
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System Name PowerSpec 1720 (Clevo PB70EF-G)
Processor i7-8750H (UV)
Motherboard PB70EF-G
Cooling Air
Memory 32GB 3000MHz 16-18-18-36 1T (OC)
Video Card(s) 115W RTX 2070 8GB GDDR6 (OC/UV)
Storage 500GB WD Black NVME
Display(s) 144Hz G-Sync 17.3" IPS (OC)
Case PowerSpec
Audio Device(s) Sound Blaster Pro-Gaming X
Power Supply 230W
Mouse Logitech G502 Hero
Keyboard Per-key RGB
Software M$ Windows 10 Pro, Throttle Stop 929, MSi Afterburner, ParkControl
Benchmark Scores CB R23 - 8173/1105, CB R20 - 3172, Fire Strike - 18140, Time Spy - 8287

yabinda

New Member
Joined
Nov 30, 2020
Messages
9 (0.16/day)
Run msconfig, click on the Boot tab and press the Advanced options... button.
Make sure the Number of processors box is not checked.
Press OK, reboot and maybe Windows will find the rest of your missing CPU.



Edit - You might want to also enable Speed Shift Technology in your BIOS. While you are in there, make sure hyper threading is enabled.
Thanks. Problem solved with bios adjustment following your instructions. It's wired as I have never touched anything in the bios before.

A follow-up question is previously the CUP speed was locked at around 4.2 GHz. Now it drops to 3.95 GHz. Any ideas?
 

unclewebb

ThrottleStop & RealTemp Author
Joined
Jun 1, 2008
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speed was locked at around 4.2 GHz. Now it drops to 3.95 GHz. Any ideas?
Intel CPUs vary their speed based on power consumption and on how many cores are active. When you enable hyper threading, you have increased power consumption. That might have something to do with what you are seeing.

Did you enable Speed Shift in the BIOS yet? If you do you will see SST in green in HWiNFO. Most laptops perform better when this feature is enabled.
 

yabinda

New Member
Joined
Nov 30, 2020
Messages
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Thanks for your reply. Yes, I did enable the speed shit in the BIOS. I also disabled the C states control. Hopefully, it has nothing to do with the speed drop.
 
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