RE: BIOS BUG REPORT: XPS 15 9550, CPU Speed capped after switching from battery to AC power

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The interim 1.1.13 and 1.1.14 bios versions are withdrawn. These versions solved speed cap issues, gave also full single core CPU speed on battery, improvements of the battery runtime with NVMe configurations (devSleep bug). But no overall battery-runtime, which was apparently one of the goals (1Hr+ ??) of Dell.

Source: www.notebookcheck.net/Dell-XPS-15-9550-i7-512GB-UHD-InfinityEdge-Notebook-Review.156462.0.html

Waiting voor a 1.1.15+ version, this or next year ??

boidsonly
2 Bronze

RE: BIOS BUG REPORT: XPS 15 9550, CPU Speed capped after switching from battery to AC power

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I can understand them wanting to fix the runtime issue since it can open Dell up to false claims of performance (GTX 970 anybody?) but, personally, that 1hour+ means nothing to me.  I would have been happy with the throttle/NVMe fix.  Let's see how long it takes to iron out that runtime issue, assuming it is at all possible.

Dell XPS-15 9550

Dell Desktop Alienware Aurora R7

HP Desktp Envy 750-175se CTO

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ejyankees
1 Copper

RE: BIOS BUG REPORT: XPS 15 9550, CPU Speed capped after switching from battery to AC power

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I have same issue as reported by you

Same issue with  Bios version 01.00.07  Build date Dec-16-2015

In power option Would set min and max processor state to "100"  

on battery it would get to 2.57 witch is fine  considering max shown as 2.60 and it is battery after all need to conserve a bit lol

but as soon as I plug the AC it lowers speed to 1.66 instantly (capping  when AC plugged in) but when unplug it will go up to 2.57

putting computer to sleep with AC on will boost to 2.60 -2-78 considering laptop don't have a load.

also  FYI  not sure if that's by design Did a stress test and I was not able to get CPU speed higher then 3.07-3.10  it  was  advertised 3.60 I believe.

Wish the manufacturer's stop misleading the promised specification.

Hope they will fix this bug/settings in future updates soon as this is suppose to be premium line XPS after all lol sure seems to be when it is priced that way.

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kirkd
5 Rhenium

RE: BIOS BUG REPORT: XPS 15 9550, CPU Speed capped after switching from battery to AC power

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Several comments:

Speed Step should usually be defeated. Then you shouldn't need to set min and max speeds to 100%. Did you set both the battery and AC sections to 100%? You did not specify but I assume you did both.

Periodic slow downs can be caused by overheating. After cooling because of the slower clock, speed increases to the max, thwn cycles downand up. Did anyone check CPU/GPU temperatures? Could be a problem with the BIOS temperature/fan control program.

This type of problem has occurred before, and was caused by underpowered power supplies. Increasing to the next higher output supply cured the problem. However, this could also be a BIOS issue where the voltage/current values that the BIOS uses to determine if enough power is available to both run the laptop and charge the battery.

Sorry I don't have a pat answer. These problems can be difficult to solve.

XPS M1530, Win 10 CU Pro 32-bit
Inspiron E1705, Win 10 CU Pro 32-bit
Dimension 9100, Win 10 AU Pro 32 bit
Inspiron 660, Win 10 CU 64 bit
Inspiron 3668, Win 10 CU 64 bit
Asus T100 Tablet, Windows 10 CU 32 bit

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ejyankees
1 Copper

RE: BIOS BUG REPORT: XPS 15 9550, CPU Speed capped after switching from battery to AC power

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Yep both set at 100% so to see the diference

when on battery it always gets in the 2.5 with max 2.6 but as soon as plugging AC drops instantly to 1.6 restart/sleep bring the  clock speed up on AC.

Did clean install same issue.

hoping for that miracle patch lol

Thanks

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ivan92
1 Copper

RE: BIOS BUG REPORT: XPS 15 9550, CPU Speed capped after switching from battery to AC power

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Hi everyone, just a quick question that may be stupid. When they eventually release this updated bios to fix the problem, can you update your system to the latest bios from an older version? i.e I am running 0.5 however the latest bios available is 0.7. Will it damage my computer to update from my current bios?

Thanks

Ivan

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ivan92
1 Copper

RE: BIOS BUG REPORT: XPS 15 9550, CPU Speed capped after switching from battery to AC power

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Hi guys,

Might be a stupid question but if they manage to fix this problem in the new bios, will I be able to safely install it from an older version of the bios? i.e I am running bios 1.00.05 as opposed to the latest available version being 1.00.07. Do I need to first update to 0.7?

Thanks

Ivan

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RemySphere
1 Copper

RE: BIOS BUG REPORT: XPS 15 9550, CPU Speed capped after switching from battery to AC power

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If not stated otherwise, you should be able to jump from one another without going through all the versions, as common BIOS updates erase then rewrite the whole dedicated EEPROM.

boidsonly
2 Bronze

RE: BIOS BUG REPORT: XPS 15 9550, CPU Speed capped after switching from battery to AC power

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I sure hope this is a BIOS issue and not something as sinister as an underpowered PS.  If it is indeed a PS issue, Dell needs to immediately stop the sales of all XPS 15 9550 machines.  Then figure out how to best handle the problem with machines sold.

It never occurred to me they would be naive enough to under power this laptop.

Dell XPS-15 9550

Dell Desktop Alienware Aurora R7

HP Desktp Envy 750-175se CTO

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nonforma1
1 Copper

RE: BIOS BUG REPORT: XPS 15 9550, CPU Speed capped after switching from battery to AC power

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Is there any update on the release of the BIOS revision with this bug fix? If mid-December is still the timeline and that review site is correct re multiple withdrawn BIOS fixes then I'm concerned this isn't going to be a similar software fix as with the 9530.

It's good that testing caught issues with the revision before general release, and it will need more time before it's available, but please continue to communicate status of the issue and expected resolution/timeline.

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