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Z840 with dual E5-2673 V4s not boosting cores beyond base clock

HP Recommended
Microsoft Windows 10 (64-bit)

Hi everyone,


I have a Z840 with dual E5-2673 V4s. My problem is that it is not able to boost any core beyond base clock. For example, on Cinebench R20 I get all 80 threads to run at 2.295MHz which is the base clock, giving me a score of ~10200 pts. When  I run it on a Single thread, this thread runs again at 2.3GHz!


FYI, HWiNFO64 has red colored the VMX option (I have disabled it in the BIOS) + the Turbo option. I tried to find something relevant in the BIOS but just couldn't.

In case it matters, on startup I also get a 921 - Front USB not Connected error that I am not able to fix. Of course all USB cables are connected to the board... and I can't even bypass it (have to press enter to continue).

HWiNFO64's full report on my CPUs is as follows:


CPU MFM (LowPower): 800.0 MHz = 8 x 100.0 MHz
CPU LFM (Minimum):
1200.0 MHz = 12 x 100.0 MHz
CPU HFM (Base):
2300.0 MHz = 23 x 100.0 MHz
CPU Turbo Max:
3600.0 MHz = 36 x 100.0 MHz [Unlocked]

Turbo Ratio Limits - IA/SSE, Fused: 36x (1-2c), 34x (3c), 33x (4c), 32x (5c), 31x (6c), 30x (7c), 29x (8c), 28x (9c), 27x (10c), 26x (11-20c)
Turbo Ratio Limits - IA/SSE, Resolved: 36x (1-2c), 34x (3c), 33x (4c), 32x (5c), 31x (6c), 30x (7c), 29x (8c), 28x (9c), 27x (10c), 26x (11-20c)
Turbo Ratio Limits - AVX2, Fused: 28x (1-2c), 26x (3c), 25x (4c), 24x (5-20c)
Turbo Ratio Limits - AVX2, Resolved: 28x (1-2c), 26x (3c), 25x (4c), 24x (5-20c)

CPU Current: 2294.8 MHz = 23 x 99.8 MHz @ 0.8890 V
LLC/Ring Maximum: 2700.0 MHz = 27.00 x 100.0 MHz
LLC/Ring Current: 2693.9 MHz = 27.00 x 99.8 MHz


Which would seem to suggest that at the very least I could expect an all core boost of 2.4GHz on AVX2 or 2.6GHz on SSE which I just never see. Any suggestions as to why this may be and what I can do to fix it? Current BIOS is 02.48. Thanks in advance!

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Message 2 of 3
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HP Recommended

I have a Z440 with a E5-1650 V3 processor and Turbo Boost worked as expected until i updated the BIOS about two years ago. I have updated the BIOS everytime a new version is released, but Turbo Boost has not come back. I have Turbo Boost enabled in the BIOS. 


So i have no solution to none of your problems but can confirm that there seems to be an issue with the Turbo Boost in a Z440 as well.

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Message 3 of 3
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HP Recommended

Finishing up a Z420 optimized build.... the BIOS settings for Turbo Mode on that might help you, and I'm running latest ZX20 BIOS on these:


Turbo Mode stays enabled if PCIe Performance Mode is Disable (Power tab section), CECP is set to Disable, Turbo Mode is set to Enable, and Runtime Power Management is set to Enable.  And, KEY, on an OS level Power settings in Control Panel is set to Performance.

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