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Flex 5-1570 (Type 81CA) Laptop (Lenovo) & BIOS V2.07 (4qcn43ww) = EXTREME THROTTLING TO 0.4Ghz

2018-07-10, 16:38 PM



my CPU is i7-8550u and my GPU is MX150.


V2.05 of the BIOS (4qcn41ww) works well. However, the big issue is that the fan curve is so high that fans will spin 24/7, even on idle. 

The laptop is able to overclock/underclock in response to demand needs. Excellent, but too loud.


I upgraded to V2.07, which definitely fixed the fan curve problem, especially when "Quiet Mode" is selected in the BIOS. HOWEVER, there is one extreme issue, the clock speed will be fixed to a single speed indefinitely until reboot. The clock speed is not able to dynamically change. This is terrible because it either is fixed to 0.4Ghz (EXTREMELY SLOW) or 1.8Ghz (still slow, bearable, but I shouldn't have to deal with this in my purchase). These clock speeds were provided by Windows Task Manager. The throttle starts at a random time, and doesn't end until the computer is rebooted.


After dealing with V2.07, I've reverted to V2.05 (provided by a Lenovo Chat assistant). I'm back to loud fans, but a properly running device.


This issue is not heat related, I don't think. I have a CPU temperature reading, and it throttles to 0.4Ghz even at 45C (which is idle). 

I've attempted to fix this problem, if it may be thermals, by applying an undervolt via Throttlestop. However, the issue persists regardless of it throttlestop is running or not. I've ran an Official Lenovo Hardware Scan, and my computer comes up clean.


For a $1000 laptop, I'm really surprised at how shoddy of a job V2.07 BIOS is. It's completely unusable for my device. I'd really like this issue to be looked at by Lenovo Technicians, as this may be a coding error, not a hardware related one. To be forced to deal with either loud fans (V2.05) or constant throttling (not thermal throttling) is horrendous. Please consider finding and fixing this issue for V2.09.


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Re: Flex 5-1570 (Type 81CA) Laptop (Lenovo) & BIOS V2.07 (4qcn43ww) = EXTREME THROTTLING TO 0.4G

2018-07-16, 23:30 PM
Run ThrottleStop. Open up the TPL window and enable Speed Shift. Go back out to the main screen and set the Speed Shift EPP value to 80. This will allow full performance when needed and it will down clock when idle.
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