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BIOS BUG REPORT: XPS 15 9550, CPU Speed capped after switching from battery to AC power
I noticed a very similar bug for a Dell Latitude posted on this forum and am shocked that Dell has not fixed these bios bugs.
I have a brand new XPS 15 9550 and I noticed that when you connect AC power after being on battery power, the CPU frequency gets capped at 1.69 GHz as opposed to the usual 3.5 GHz. The only way to fix this is to then reboot or sleep/resume the system. What is the best way to report this BIOS bug to Dell? There has to be some way to get Dell to fix the issue in a BIOS update.
I have found several other users also complaining of this same issue:
forum.notebookreview.com/.../help-needed-from-new-xps-owners-report-serious-bios-bug-to-dell.783715
I really hope Dell fixes this issue since it is unacceptable for Dell to sell such an expensive and premium machine with a glaring firmware bug that turns your i7 performance into a Pentium level of performance.
RemySphere
9 Posts
0
November 21st, 2015 04:00
Same problem here, among other things like Wi-Fi card causing a blue screen then not starting up again... Had to uninstall the driver completely, download it from dell's website and reinstall it to get Internet back.
Also, the audio produces heavy static noises when I change the brightness of the screen while listening to music or so.
Also, the screen flickers at low brightness levels, not heavy yet, but if I notice it it's not good.
Also, the fans are going crazy, running almost all the time at an way too audible state.
But the MOST annoying of it all, is that a €1400 computer I received within 25days, after arguing with the worst commercial employee of all time for a "student discount' that she made clear I didn't deserve, is running at the incredible speed of 1.6GHz after unplugging the cord the first time.
i5, 1T SSHD, 8GB RAM, 960M and Full HD display.
I'm using it since this Tuesday, as a replacement for my MacBook Pro, this is ***. I don't care about fixing the issues, this is a HIGH END COMPUTER FOLKS. Now I have to find a good competitor again.
RaymondCDijkstra
8 Posts
1
January 2nd, 2016 04:00
forum.notebookreview.com/.../page-48
Seems that bios 01.01.15 is out.
I can confirm speedcapping issue is gone (i7, 4k, 1tb ssd, 16gb).
Processor SST is (still) not available.
TPM still disabled.
============================
Haris163 did find out: I was just able to update the BIOS to 01.01.15 using the update driver software option from the device manager.
My reply:
Nice find, thanks for the update.
I noticed 4 firmware update:
1) system bios update (I think that was the text, since I started writing things down after I noticed their were 4 updates);
2) Intel ME firmware update;
3) Main TI PC 0
4) EC Bios
Anyone knows what 1..4 means??
Geekbench gives same results running on battery and AC, both ways peaks multicore at 3,3 Ghz and 3,5 Ghz singlecore.
DELL-Colin Hu
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351 Posts
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January 5th, 2016 02:00
Hi Everyone,
The 01.01.15 BIOS is now live on the Support site here. Only install the update from our support site, don't force the update through Windows Update as it is only a partial update and doesn't include all the fixes that are contained in the BIOS update.
The fixes in the update include:
1. Improve Audio performance
2. Improve NVMe Battery Life
3. Fix CPU i7 CPU performance became low after AC remove and insert.
4. Enhance system Boot time
5. Fix System may saw NO Boot Device error message with NVMe storage.
6. Enhance battery mode sleep resume time too long.
Please install the BIOS and check if all the issues are resolved that you have been experiencing on the 9550
Thanks everyone for your patience while the issues were being worked on and being tested to make sure they were resolved.
DELL-Colin Hu
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351 Posts
2
November 10th, 2015 02:00
Thanks for bringing this to our attention, I'll pass it on to our engineering team to see if they are aware of this on the system and if there is a fix for it
unlabeled
8 Posts
0
November 10th, 2015 08:00
Thanks Colin. It is otherwise a fabulous machine, I just hope Dell can address this issue soon.
d3msd8le
33 Posts
1
November 10th, 2015 12:00
Reporting the same problem on a new XPS 9550. BIOS 01.00.05.
As OP mentioned, after switching to battery, CPU frequency is capped around 1.69 GHz and only way to re-enable full speed is to sleep or reboot. Plugging in to AC does not re-enable full speed.
byunnbi
10 Posts
1
November 10th, 2015 15:00
I'm also throwing my hat into the ring to confirm the same annoyance. I too agree, this is simply unacceptable. I noticed this problem both before and after the BIOS update via provided .exe on Dell's driver download page for 15-9550.
DELL-Colin Hu
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351 Posts
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November 11th, 2015 05:00
So we can get some more information on this issue and to try and resolve it, can you answer a few questions for me:
1. How long does it take when running on Battery for this to occur?
2. If you disable C State, Intel Speed Step or Turbo Boost does anything change?
Thanks
d3msd8le
33 Posts
1
November 11th, 2015 06:00
>1. How long does it take when running on Battery for this to occur?
The instant you unplug, CPU downclocks (as it should). Plugging in to AC afterwards will not bring the clock back up. You need to sleep or reboot to get the clock back to AC speeds. If you reboot/sleep, then the clock is instantly back at full speed when the machine wakes.
>2. If you disable C State, Intel Speed Step or Turbo Boost does anything change?
Tried them all. Disabling C State and Turbo Boost did not solve the problem. Turning off Speed Step has the processor running at the full speed all the time, even on battery, regardless of plugging in/out etc. Turning off Speed Step is obviously not a realistic option for laptops.
DELL-Colin Hu
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351 Posts
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November 11th, 2015 07:00
Thanks for the info.
I've passed it on and the issue is being looked at by our Engineering team
unlabeled
8 Posts
1
November 11th, 2015 08:00
I can confirm that my observations are consistent with all of d3msd8les comments.
Speed step does block the CPU from getting locked in at a lower frequency but of course isn't feasible to use for long term in a laptop due to excessive heat and fan noise.
Using 3rd party tools like ThrottleStop and manually increasing the CPU multiplier can also force the CPU frequency back but this is a hack and more or less means the CPU always run high frequency which again isn't very desirable in a laptop. In general you don't want to use a 3rd party application to try to fight what the firmware is trying to do, much better to fix the bug in the bios.
DELL-Colin Hu
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351 Posts
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November 13th, 2015 04:00
Hi,
So we've done some investigating into this issue and we have an engineering version of the 9550 and we couldn't replicate this particular issue.
We have released a new revision of the 9550 BIOS <ADMIN NOTE: Broken link has been removed from this post by Dell> today. Can you please apply the BIOS update and check if it still has the CPU problem. If the problem still occurs let me know
byunnbi
10 Posts
2
November 13th, 2015 07:00
Colin, first, thanks to you and your engineering team for looking into the issue.
Unfortunately the BIOS update (1.0.0.7) did not resolve the issue. I will add that I tried replicating the issue while setting the Windows Power Setting to "high performance" as well as "balanced" (all default settings) but the CPU clock remains capped at 1.66ghz even after plugging the power adapter back in.
As OP had posted, it remains the case that either restarting or sleeping/waking the system will resume normal CPU function both on battery and on AC adapter, at least until the next time I unplug/plug the power again.
Out of curiosity, what did engineering change in BIOS 1.0.0.7 that was supposedly to solve this issue? Is it related to the power-flickering issue that the same version was supposed to address, and is the power-flickering issue other users have been reporting elsewhere related to this CPU clock problem?
unlabeled
8 Posts
1
November 13th, 2015 08:00
Colin, Thanks for looking into this. I will try the new BIOS and report back but it sounds like that probably won't do it based on the other user's report.
Are you sure the engineering team followed the proper steps to reproduce this?
This is now a widely reported with plenty of users reporting the same problem:
forum.notebookreview.com/.../help-needed-from-new-xps-owners-report-serious-bios-bug-to-dell.783715
That link also has specific steps to reproduce.
arjunprabhu
6 Posts
1
November 13th, 2015 09:00
i can confirm this bug as well.
here is my situation:
Config : i7/512GB/16GB RAM/4k
Steps to reproduce and observation:
Btw, i am on the latest firmware/bios released today (11/13) - 1.0.0.7.