Question Intel i7-7700 CPU performance has dropped by 50% suddenly.

Jan 8, 2020
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I have written a chess engine in C++ which uses a single thread at 99% CPU busy. In November and previously, a test position from the initial set up, looking ahead 17 moves, used 20.9 seconds of CPU time consistently under Windows 10. Now the same calculation uses 63.5 seconds consistently when no other major tasks are using the CPU. The thread is still running at 99+% and the same number of chess positions are evaluated as before ( 50,021,849 ). The CPU still gets 3.6 to 4.1 GHz. Windows 10 has updated to 1903 which may be a coincidence, since I have turned off all apps using significant CPU time. Nothing else shows up on the monitors, and my power settings are high performance and sleep NEVER. The CPU just seems to take 2 - 3 times as much time to process the same program as before. Is it hardware or software at fault? The BIOS is from HP as is the hardware. 8 GB ram and 500 GB SSD. No bottlenecks except CPU busy.
 

Lutfij

Titan
Moderator
We're currently on 1909 and we're awaiting a latter version. Might want to see if you can update to that within Windows or you're going to have to try and reinstall the OS after creating the bootable installer using Windows Media Creation Tools.

Also, for your platform, make sure you're on the latest BIOS update prior to the updates for the OS.

HP prebuilt system? SKU please?
 
Jan 8, 2020
2
0
10
I have written a chess engine in C++ which uses a single thread at 99% CPU busy. In November and previously, a test position from the initial set up, looking ahead 17 moves, used 20.9 seconds of CPU time consistently under Windows 10. Now the same calculation uses 63.5 seconds consistently when no other major tasks are using the CPU. The thread is still running at 99+% and the same number of chess positions are evaluated as before ( 50,021,849 ). The CPU still gets 3.6 to 4.1 GHz. Windows 10 has updated to 1903 which may be a coincidence, since I have turned off all apps using significant CPU time. Nothing else shows up on the monitors, and my power settings are high performance and sleep NEVER. The CPU just seems to take 2 - 3 times as much time to process the same program as before. Is it hardware or software at fault? The BIOS is from HP as is the hardware. 8 GB ram and 500 GB SSD. No bottlenecks except CPU busy.
We're currently on 1909 and we're awaiting a latter version. Might want to see if you can update to that within Windows or you're going to have to try and reinstall the OS after creating the bootable installer using Windows Media Creation Tools.

Also, for your platform, make sure you're on the latest BIOS update prior to the updates for the OS.

HP prebuilt system? SKU please?
HP prebuilt product ID 00325-95800-00000-AAOEM ( is that same as SKU ? )
I just upgraded to 1909 and CPU time is identical to 1903 ( slow )
I still need to check BIOS but HP sends me updates every few weeks. There was one in December.