The Notebook Review forums were hosted by TechTarget, who shut down them down on January 31, 2022. This static read-only archive was pulled by NBR forum users between January 20 and January 31, 2022, in an effort to make sure that the valuable technical information that had been posted on the forums is preserved. For current discussions, many NBR forum users moved over to NotebookTalk.net after the shutdown.
Problems? See this thread at archive.org.

    Undervolting - Pros & Cons

    Discussion in '2015+ Alienware 13 / 15 / 17' started by Colonel Panic, Dec 19, 2016.

  1. Colonel Panic

    Colonel Panic Notebook Guru

    Reputations:
    3
    Messages:
    65
    Likes Received:
    14
    Trophy Points:
    16
    Hi guys

    In almost all the threads I read about the 15R3 and 17R4, regardless of CPU, I hear people suggesting to undervolt by .100 to .150 using XTU. The end result is people posting reduced temps across the board and what seems like higher sustained clock frequencies. My question is as follows:

    Are there any cons? (I don't understand why Intel/Dell/AW wouldn't just set it this way from the factory...)
    Are there any other pros than the ones mentioned above?

    After 2 exchanges, my 3rd unit arrived with awesome temps (not much variation and maxing out in the high 70's rarely). I've got some minor light bleed, but seem to have ended up with a brighter, whiter panel with slightly better colours (both Sharp 4K's but one being produced nearly a year later than the other).
     
    hmscott and Mobius 1 like this.
  2. Porter

    Porter Notebook Virtuoso

    Reputations:
    786
    Messages:
    2,219
    Likes Received:
    1,045
    Trophy Points:
    181
    The only con I can think of with an UV, is if you go too far the system will be less stable. You will get weird crashes doing certain tasks while it may run for days doing others.

    As long as you don't go too far, there are no downsides. It's better for the CPU, less heat, more speed for you. It's basically that last fine tuning you are doing for Intel, as every chip is different and they run them all at a higher voltage to insure they all will run out of the box. It takes time and any mass manufacturer won't want to spend that time to fine tune it, which is why we have to.
     
    Last edited: Dec 19, 2016
  3. Mobius 1

    Mobius 1 Notebook Nobel Laureate

    Reputations:
    3,447
    Messages:
    9,069
    Likes Received:
    6,376
    Trophy Points:
    681
    bingo
     
    el_pitaya, Vasudev and hmscott like this.
  4. judal57

    judal57 Notebook Deity

    Reputations:
    274
    Messages:
    1,164
    Likes Received:
    650
    Trophy Points:
    131
    Dell and all brands dont make undervolt at stock because each cpu is different ... if you want to know more search on google : silicon lottery hahahahahahah
     
    hmscott likes this.
  5. ElCobrito

    ElCobrito Notebook Geek

    Reputations:
    0
    Messages:
    77
    Likes Received:
    26
    Trophy Points:
    26
    Actually I undervolted my 13R3 by -180, and it seems that was enough to avoid repasting. I've got to admit undervolt is awesome.
    Cons are just crashes, so you've got to test how far you can go before getting BSODs.
     
    Vasudev and hmscott like this.
  6. Pete Light

    Pete Light Notebook Deity

    Reputations:
    172
    Messages:
    1,052
    Likes Received:
    643
    Trophy Points:
    131
    Fair enough but I'd say that another con is you can't overclock vs a properly repasted CPU which can then run at a higher voltage no?
     
  7. Vasudev

    Vasudev Notebook Nobel Laureate

    Reputations:
    12,050
    Messages:
    11,278
    Likes Received:
    8,815
    Trophy Points:
    931
    Too much UV is also a problem, you lose the performance for which you've paid. I would benchmark using XTU and if the difference in scores in <5 points, then you've a good UV with less performance hit.
     
  8. ElCobrito

    ElCobrito Notebook Geek

    Reputations:
    0
    Messages:
    77
    Likes Received:
    26
    Trophy Points:
    26
    I don't know, I've read people saying that they could overclock the gpu since they had lower temperatures thanks to cpu undervolting, and I'm not interested in overclocking CPU. Anyway I'm sure repasting is preferable but it's also immensely more risky.

    Actually 3d Mark score increased. I'm not an expert in undervolting but I think that if you go too low you just get errors instead of reduced performances.
     
  9. Mobius 1

    Mobius 1 Notebook Nobel Laureate

    Reputations:
    3,447
    Messages:
    9,069
    Likes Received:
    6,376
    Trophy Points:
    681
    if you go too low the whole system will crash

    undervolt will improve score because it gives a bigger headroom for the turbo boost to do work when the cpu is heavily loaded
     
    SimplyJ3sse and Vasudev like this.
  10. taraquin

    taraquin Notebook Consultant

    Reputations:
    21
    Messages:
    280
    Likes Received:
    79
    Trophy Points:
    41
    Undervolting will in many cases increase performance, not reduce it. Reason: Lower temp allows cpu to maintain turbospeed at higher load. Many NBs has shared heatpipes between cpu and gpu, so UV on cpu reduces temp and hence increases tubo-output on gpu aswell :) I actually managed to undervolt my 6700HQ to -185 stable, and that did something dramatic with cpu-temps and a slight difference on gpu-temp. Only downside is BSOD, at -186 I got them now and then, at -185 I never get them, atleast none som far after 1 month :)
     
  11. Vasudev

    Vasudev Notebook Nobel Laureate

    Reputations:
    12,050
    Messages:
    11,278
    Likes Received:
    8,815
    Trophy Points:
    931
    I lost 10-20 points in XTU after UV'ing to -180mV that's why I chose -30mV(AC) and -75mV (battery mode) and also defaults when running benchmarks.
     
  12. judal57

    judal57 Notebook Deity

    Reputations:
    274
    Messages:
    1,164
    Likes Received:
    650
    Trophy Points:
    131
    that 20 points dont mean at least 0,0000000001 fps on games hahahah but can mean 5 grades less
     
  13. vkt62

    vkt62 Notebook Consultant

    Reputations:
    2
    Messages:
    241
    Likes Received:
    49
    Trophy Points:
    41
    So do you use the Bios overclocking page to undervolt or do you use XTU. And if not, can you use the Bios to set the performance settings?


    Sent from my iPhone using Tapatalk
     
  14. el_pitaya

    el_pitaya Notebook Consultant

    Reputations:
    29
    Messages:
    216
    Likes Received:
    1
    Trophy Points:
    31
    can you undervolt using bios?

    Also, are you guys overclocking the i7-6820HKup to 4.1 Ghz?
     
  15. vkt62

    vkt62 Notebook Consultant

    Reputations:
    2
    Messages:
    241
    Likes Received:
    49
    Trophy Points:
    41
    That's what I would like to know also


    Sent from my iPhone using Tapatalk
     
  16. Vassilis008

    Vassilis008 Notebook Consultant

    Reputations:
    9
    Messages:
    159
    Likes Received:
    58
    Trophy Points:
    41
    I am getting too many bugs with bios overclocking - just use throttlestop instead for o/c and xtu to unlock the power limit :)
     
  17. Lozz

    Lozz Top Overpriced Dell

    Reputations:
    536
    Messages:
    2,087
    Likes Received:
    22
    Trophy Points:
    56
    You can not use BIOS to undervolt.
     
  18. vkt62

    vkt62 Notebook Consultant

    Reputations:
    2
    Messages:
    241
    Likes Received:
    49
    Trophy Points:
    41
    Ok but do the updated processor settings activate on powerup or once windows loads if I used Throttlestop or XTU?

    Also, do the softwares have to run in the background?

    And finally which is better? Throttlestop or XTU?


    Sent from my iPhone using Tapatalk
     
  19. Mobius 1

    Mobius 1 Notebook Nobel Laureate

    Reputations:
    3,447
    Messages:
    9,069
    Likes Received:
    6,376
    Trophy Points:
    681

    xtu is only used to set power limit, everything else is done through ts
     
  20. Philosobyte

    Philosobyte Notebook Enthusiast

    Reputations:
    7
    Messages:
    42
    Likes Received:
    15
    Trophy Points:
    16
    I'm not a gamer, so I thought my -180mV undervolt was fine when it could run OCCT for five minutes at stable temps. I started a CCleaner run while compiling in Unity and doing Chrome stuff. Fifteen minutes later, I clicked on Chrome in the taskbar, a popup told me "reference not found," and the computer restarted to a black screen, meaning the OS was corrupted (I don't think CCleaner would have corrupted my computer if I hadn't undervolted because I'd been using CCleaner weekly for quite a few months). This incident happened near school final project deadlines, so I would have been completely screwed if not for a spare flash drive with Ubuntu which I used to pull personal files off of the corrupt partition and redownload Windows.

    A couple weeks later, I tried undervolting 180mV again and decided to run OCCT until it crashed. It crashed after about fifteen minutes.

    The takeaway from this is that although an undervolt crash normally won't corrupt your OS, I still recommend not to skimp out on your stability testing to avoid the potential of getting screwed in the future.
     
    Pete Light likes this.