ThinkPad X1 Extreme is louder after BIOS update
Our review periods are usually limited to a few days or weeks, but manufacturers continue to provide updates. This might be to improve certain aspects or fix bugs, and these updates can have a big impact. After our two comprehensive reviews of the ThinkPad X1 Extreme, we were contacted by some owners with problems of the fans in everyday situations. There is also supposed to be a problem with activated virtualization. We did not notice these issues in our original reviews, so we organized another test unit of the ThinkPad X1 Extreme to check the impact of the latest BIOS updates.
We now used the X1 Extreme as our primary working device for a few weeks, and we can confirm that the fans start much quicker under load with BIOS 1.17. A look into Lenovo's BIOS change log (probably) identifies version 1.15 as the reason with the item "Improved thermal function". The maximum fan noise is the same and we cannot see lower surface temperatures under load, either.
This behavior was very annoying in practice, because even short peak load on mains triggered the fans despite undemanding tasks. This was definitely not the case before and it looks like Lenovo recognized the problem as well, because the BIOS update 1.19 introduces the item "Improved thermal function to improve FAN behavior".
However, the result is not very convincing. The fans kick in a little bit later compared to 1.17, but the situation is still worse compared to our initial review. It does not matter what setting of the performance slider you select, even a couple of browser tabs or 2-3 running applications (Word, Outlook, Chrome) are sufficient. Sometimes, there is no apparent reason at all and the fans kick in while idling on the desktop. We know this behavior from other current ThinkPads like the X1 Carbon. The situation is better on battery power, but this cannot be the solution for a powerful laptop. Lenovo should definitely improve the fan control.
According to some reports (including topics in Lenovo's service forums), there seems to be an issue with the processor performance when Intel's virtualization technology (or Hyper-V, respectively), is active in the BIOS. This would affect users running virtual machines, for example. The reports show a temperature limit of 80 °C for the CPU, which would obviously affect the performance. The examples also include Cinebench tests, the same we use in our reviews.
However, we cannot confirm the temperature limit. We see CPU temperatures of ~97 °C in the Cinebench R15 Multi test both with activated and deactivated virtualization. Overall, the performance with activated virtualization (default) is even slightly higher. The result drops a bit after the first iteration, but this applies for both scenarios. The overall performance is a bit lower compared to our initial review unit though. We cannot say for sure whether this is related to the BIOS updates or if it just a worse example of the Core i7-8750H.