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2 Bronze

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.

 

Replies (159)
2 Bronze

My problem turned out to be the latest Nvidia driver that cam out last week.  Seems to hit mostly with Adobe apps like Photoshop.  If anyone starts seeing this roll back to the last Nvidia driver in device manager.

2 Bronze

Or use the latest NVidia driver & delete or rename sniffer.exe in the Adobe directory. Adobe has sometimes (for years) problems with machines with multiple GPU cards & certain drivers. Adobe causes a BSOD (kernel_security_check_failure)

Moderator
Moderator

Hi Everyone,

I was away for the Holidays, but have came back today.

I know the Mid-Dec date I was given for the BIOS  has been missed and I apologise for that, it looks like the update has taken longer than expected to be ready.

The 01.01.15 update that people are getting through Windows Update; ***EDITED***don't install it as it is a partial update. Only install the BIOS update through the Dell Support Site

Colin H
Dell | Social Outreach Services

I'm based in the UK and available Monday to Friday 9am-5pm GMT


2 Bronze

"Or use the latest NVidia driver & delete or rename sniffer.exe in the Adobe directory. Adobe has sometimes (for years) problems with machines with multiple GPU cards & certain drivers. Adobe causes a BSOD (kernel_security_check_failure)"

For me it was an issue when running Handbrake or Lightroom.  In the Nivida forums others are reporting issues with other programs as well.

Moderator
Moderator

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.

Colin H
Dell | Social Outreach Services

I'm based in the UK and available Monday to Friday 9am-5pm GMT


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2 Bronze

Hi Colin,

Well this is great news and thanks for the update!  It's taken some time but good things come to those that wait. :-)

Cheers

2 Bronze

Fix CPU i7 CPU performance became low after AC remove and insert.

Can someone confirm this fix also work for the i5 CPU ???

2 Bronze

Go ahead install it, i5 is flying now, hitting 3.12ghz all the time, on battery and AC. Was going to sell this laptop keeping it now.

2 Bronze

First of all thanks for the update. 

I can confirm that some issues were resolved. Battery life increase is quite noticable from what I can say by now - like about an hour more than before. 

However: 

CPU Speed gets still capped to 1.69GHz on battery, but at least goes back up to 3.1GHz, as soon as its plugged in. 

The bios boot time has pretty much tripled from about 10 seconds to more than 30 seconds. I've already spoken to dell tech support, who are pretty much clueless. ***, my 4 year old 800€ laptop boots within 4 seconds while my brand new 2200€ machine takes 30 *** seconds to even initialize Windows? 

My config is: UHD Display, 6700HQ, 512GB SSD (PM951), 16GB RAM.

Furthermore one out of three boot attempts leads to being stuck at the dell logo for minutes until I reboot. This has been this way before the bios update, but I was hoping the update would resolve this issue aswell. I ran this dell diagnostics software from the boot menu and it gave me an error for the SSD, however the dell tech support guy told me, the software doesn't work for NVMe drives yet, so I cannot even tell if it's a defective SSD or some software hickup.

May be related to point 5 in Colins list. 

Has anyone else experienced this kind of behaviour? Seems like the boot time increase is related to the bios update in some form. Dell tech support will call me back later today, so I'll keep you folks updated on this issue. 

Kind regards

2 Bronze

So, after having another call with the dell tech guy, he confirmed that they have had multiple reports of in fact much slower booting after the bios update as well as being stuck at the dell logo when booting. 

According to him dell is working on yet another bios update that should resolve that issue plus some other things. It will likely take at least another few weeks to be finished...

Edit: He also mentioned that reinstalling Windows in Legacy BIOS Mode would resolve the issue of being stuck at the cost of not having Fast Boot. 

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