12-02-2018 12:19 AM - edited 12-02-2018 08:51 AM
TL;DR version: I think that BIOS 1.34 update for X1C6 botched the CPU microcode or something, which causes severe power drain, and I wish to contact Lenovo.
Edit: this could be SPECTRE-related, but I'd rather have that hole than lose half of the battery time on a laptop that cost me $1800
Long version (I'll try to make it short):
My system is:
X1 Carbon 6th Gen (20KH)
Core i5-8250U / 8GB
Windows 10 Pro
Battery at full capacity (bought the laptop in October, the battery is at about 30 cycles)
Default BIOS settings ("battery optimised" and "balanced" when on battery)
Power plan: Balanced (there are no any other plans anyway)
My usage is quite minimal: Microsoft Office, Firefox, Slack, with Google Drive and OneDrive running. For the first 1.5 months of using it, I was getting more than 10 hours of work time from the battery - I was never able to test that 15.5 hours promise, but after 10 hours of active use (i.e. minus sleep time) I still had had 25-30%.
After installing the BIOS 1.34 update via Lenovo Vantage, my battery time was cut at least in half.
The symptoms were:
- the CPU was running at the maximum frequency regardless of the power mode I selected
- the CPU temperature was around 50C (120F) or higher all the time, even on battery, while previously it had used to be at 36-38C (below 100F)
- the promised work time from the battery even in the Battery saver mode was around 6.5 - 7 hours
- EDIT: the strange thing is that everywhere - in the BIOS settings, in the OS - my CPU is shown as Core i5-8250U @ 1.60GHz, 1800 MHz. The former frequency is right, the latter is wrong - it's the base frequency for Core i5-8550U. This is one of the reasons I blame it on the updated CPU microcode.
I reverted the BIOS to the version 1.31, then to 1.30 - that didn't help, so I tried other options.
I applied this patch: https://support.lenovo.com/en/us/solutions/ht506625, and the frequencies stopped being always at the maximum, although the temperatures didn't get lower and power drain didn't stop.
I reverted the latest Windows update, that didn't help either.
I stopped the Thunderbolt service as somebody had suggested here on the forums, that too didn't help.
I decided to exclude the Windows/driver culprit version altogether, created the Lenovo USB Recovery Tool and reinstalled the Windows anew.
This screenshot was made the first time I disconnected the AC cable after the reinstall, no Windows or driver updates installed. The laptop thinks it will provide me those 15 hours:
And this one was made several minutes later after it had time to calculate the real expected time. Note that the power mode is Battery Saver:
So it was neither some Windows update nor a driver.
I believe the reason for this to be this "enhancement". Could it be that the BIOS update changed the CPU microcode and that doesn't revert when I install earlier BIOS versions?
Or maybe it was that "Improved Thermal FAN behavior", though why it doesn't get fixed with the BIOS downgraded is a mystery to me.
Does anybody have the same problem? Could anybody please suggest anything? Or where should I write so that Lenovo notices this and helps me (and presumably not just me)?
Thanks in advance.
Solved! Go to Solution.
12-02-2018 03:56 AM
Okay, here's a thought: downgrading BIOS doesn't help because previous versions didn't update the CPU microcode. Neither 1.30 or 1.31 nor any earlier version.
Wonder if the CPU microcode could be updated separately, i.e. not via a BIOS update.
12-04-2018 12:49 PM
I'm having a very similar problem. on the same machine. I've got an X1C6, but with the i7-8550u.
Ever since the 1.34 update, the laptop has lost about 80% of battery life overnight when I leave it in sleep mode. Prior to 1.34, it lost 7-12% overnight. Additionally, the fan is running WAY more often than it was previously. Just sitting here in Firefox (4 tabs) and Outlook, the fan is at full blast. Prior to 1.34, I could run Firefox, Outlook, SublimeText and a cmd prompt window without the fan making too much noise.
12-05-2018 08:03 AM
If your battery life has gone bad, can you please try this?
1. open a command prompt as administrator
2. "powercfg /energy"
3. wait a minute or so while the report is generated
4. open energy-report.html
5. are there any errors reported (highlighted in pink)? I'm especially interested to know if you see an error like this:
12-05-2018 08:53 AM - edited 12-05-2018 09:00 AM
Good morning! (It's ten minutes to midnight here, but it says you're in NC, so)
First of all, wow! Lenovo does react to posts on these forums!
Second of all (haha), yes, there are! And there are even worse-looking lines like:
"Platform Power Management Capabilities: PCI Express Active-State Power Management (ASPM) Disabled"
"Devices with missing or misconfigured drivers can increase power consumption.
Device Name Microsoft Wi-Fi Direct Virtual Adapter"
I'm attaching the whole report here. And I am ready to provide you with any help you need from me! (In several hours when I'm awake again)))
PS: btw, this wasn't in the original post. My laptop's power consumption is 9 to 10 Watts when idle (40% screen brightness), and up to 12 to 13 when I simply do something in Slack or Firefox. Just in case.
12-05-2018 09:07 AM
I think USB Selective Suspend is the problem. I suggest enabling that as the first step, then see what your battery life looks like.
Unfortunately, Microsoft hid the USB Selective Suspend setting on Modern Standby, but you can effectively enable it by restoring the default power plan settings.
1. right-click on battery icon in the notification area (next to clock)
2. select Power Options
3. For your power plan, which is probably "Balanced", click on "Change plan settings"
4. click on "Restore default settings for this plan" (near the bottom)
5. you may have to reset any timeouts for "Turn off display" and "Put the computer to sleep" that you had set previously
6. run "powercfg /energy" again, you should not see the errors about USB Selective Suspend anymore.
7. check your battery life again, is it better now?
12-05-2018 09:23 AM
You know what? It DID help!
Even though reinstalling Windows didn't! (like, what???)
It's actually fluctuating too much, and right now it says I'll only have 8 hours of battery life, but I'll report again tomorrow after I've had enough time to test it.
Thank you very much!
Btw, it still says: