CPU 45W TDP Limit

Discussion in 'Hardware Components and Aftermarket Upgrades' started by Danishblunt, Nov 21, 2017.

  1. bennyg

    bennyg Notebook Deity

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    4.2 is completely stable at stock voltage and safe for the clutzy auto fan profile. Even today as I was encoding a bunch of stuff (wrote a neat script to have multiple computers simultaneously work at encoding a large bunch of files in a network shared directory) and it was over 25C ambient inside.

    No ability to alter volts other than add turbo voltage at the high end on ivy bridge. That is what the FIVR adds on Haswell onwards.

    I don't leave fans on auto and run AVX benches at max OC on 30C+ days very often - and it was only for 20 seconds to generate those screenshots. You can only find some limits by exceeding them.
     
    Last edited: Nov 21, 2017
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  2. bennyg

    bennyg Notebook Deity

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    Just don't set to 4.0ghz first try.

    The AVX workload doesn't break the CPU... the frequency you're trying to run it at can break a CPU you may think is "stable" at sane everyday-like workloads, because if you've tuned to the limit, you'll go way past that limit when you add all that extra power and heat.
     
  3. Danishblunt

    Danishblunt Notebook Virtuoso

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    I'll do some tests later today :)

    thanks!

    also before testing I should probably repaste, because at its current state I won't be doing it :x
     
  4. yrekabakery

    yrekabakery Notebook Evangelist

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    No 45W/47W limit on this i7-4720HQ CPU with unlocked firmware.

    Here's a screenshot of it averaging 55W over a 4-minute wPrime 1024M run:
    [​IMG]

    Here is Prime95 Small FFTs (AVX) for 5 minutes at 65W:
    [​IMG]

    ^That was with TDP locked at 65W, so multiplier sat at 30x or so. We all know how AVX automatically overvolts and massively increases power consumption on Haswell. The CPU hits almost 90W if running that same test with unlocked TDP at 36x multi, reaching critical temperatures rather quickly on this notebook:
    [​IMG]

    However, with a -50mV undervolt on core and cache, the CPU can run non-AVX Prime95 Small FFTs indefinitely at 36x, sitting in the mid-50W range at low 80C's:
    [​IMG]

    These are the CPU power limits, set in BIOS, which I basically copied from a desktop 4770K:
    [​IMG]
     
    Last edited: Nov 21, 2017
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  5. hmscott

    hmscott Notebook Nobel Laureate

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    As I said, it's thermal throttling and overheating - pushing way past the cooling design limits, and probably stressing the power delivery design.

    It's not designed to do that. :)

    How much more work do you get done by having done that mod? Do you run long batch jobs in shorter time, and have more turn over in them. Is there any real gain in your day to day use?

    What are your daily running settings, what you set things to when not benchmarking - to extend the life by reducing the thermal and power stress to the system? I hope you don't run limitless extreme's all the time.

    Or do you only gain posting benchmarks once in a while? How often can you even do that?, not many people are going to know enough to be impressed. It's very nice. :)

    It's fun I'm sure to cheat the design, but really what does it accomplish?
    90740417.jpg
    And, again, that's the Haswell firmware microcode hack, I haven't heard of anyone cracking through the 6700HQ or 7700HQ microcode, have they?

    We were originally talking about giving somone advice on how to tune their locked HQ CPU through XTU / Throttlestop to get best performance, but I assumed not by making their laptop into a little Chernobyl that they would have to tweak and tune appropriately for every load, or have 100% fans shrieking in their ears while using it. Which isn't even possible for a 6700HQ / 7700HQ.

    I made one simple comment after looking at his XTU settings:

    "I don't see anyone else mentioning it, so you might want to check how high you can set the Turbo Boost Power Time Window - currently at 0.25sec, it should be at least 8 seconds, but see how high you can set it in that drop down, I've seen up to 28 seconds, but not sure what the 7700HQ is limited to.

    That's why your CPU keeps dropping Turbo Power, it's only keeping it at full Turbo Short Power for .25 seconds :)"

    It's what someone with a non-Haswell HQ CPU - or even a Haswell CPU they don't want to Chernobyl - and a tunable Turbo Boost Power Time Window would want to hear - their Window setting is too short - check the drop down menu and see if you can change it to the maximum available setting.

    @Unhappy User - have you tried that? :)

    I now think the 6700HQ / 7700HQ won't actually benefit from that change - but it won't hurt it - because the power drawn under load seems to never approach that limit.

    In my previous unhacked Haswell / Broadwell use the CPU's would at least be tuneable to draw more than 45w for up to 28 seconds, but the 6700HQ / 7700HQ don't draw that much power even under the most strenuous CPU load...

    So all of these posts just to ask a guy to try a setting have been wasted, he could have simply tried it and told us it made no difference :)

    The poor Mod's thought this was going to turn into some kind of BGA bashing, but actually we've all been pretty well behaved and not done that, it's just a fun walk through discovery of what the limits are, and why it's a waste of time to hack them for day to day operation. The design won't take the added power / thermal load enough to make the hack useful.

    Sorry if I am a bit down on over-driving hardware past it's power and cooling design limits. I started my career as an electronics repair technician for large analog / digital design companies in High School and College, and I've seen what accidental over power draws do to the hardware I have to repair. Ever since those years of hands-on experience I know that the design limits are there for a good reason, so I always work within the limits of the design and I don't think it wise to exceed them as I've seen the damage it can do.

    All that danger to your expensive hardware, just to get bragging rights that you broke your device such that it can briefly gain the performance of another design, never made sense to me :)

    To me going past the limits useful for daily use makes no sense for the majority of users looking for performance and tuning advice, they don't want to go through a bunch of axles trying to use that modded performance:

    Everyone loves watching guys blow their stuff up from abusing it, so that's another thing to keep in mind. If you don't want your stuff to blow up, don't take performance modding advice from guys with boxes and boxes of broken axles sitting in the garage. :)
     
    Last edited: Nov 21, 2017
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  6. yrekabakery

    yrekabakery Notebook Evangelist

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    It was just to show what's possible with an HQ CPU when it's freed from the shackles of stock cancer firmware. Like I said, under real-world max loads, i.e. not when running Prime95 AVX Small FFTs, TDP tops out in the mid-50W range and thermals are managed just fine by this laptop's cooling.

    Yes. In any workload that stresses the CPU at 100% for more than a minute or two, I can actually run the CPU at its full rated speed, instead of throttling.

    Those are my regular settings that I showed. 38/37/36/36 1/2/3/4/-core multis, 84W/105W long/short turbo power limts, 8s time limit, 95A current limit, -50mV core and cache. Like I said, basically copy-pasted from stock 4770K settings, so hardly extreme.

    I benchmark after physical hardware changes, when testing overclocks, after driver updates, and if I suspect performance degradation.

    Aside from that, I don't benchmark an already tuned system often.

    "Cheat the design" is a funny way of looking at it. I call it getting the performance I paid for. But we probably won't see eye to eye on this.

    I'm not running the old bugged microcode (see here), otherwise I'd be able to overclock past 3.6GHz, which I can't.
     
    Last edited: Nov 21, 2017
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  7. Unhappy User

    Unhappy User Notebook Consultant

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  8. hmscott

    hmscott Notebook Nobel Laureate

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    But, this BCLK OC hack doesn't unlock power limits... so you are still limited by 45w power limit after the Turbo Boost Power Time Window expires, right?

    A 2700K I built in 2011 is still running at 5.0ghz, probably outperforming this hack, running cool with Noctua air cooling, a bunch of Noctua fans, nearing 7 years on AS5 :)

    IDK, why not just buy a full on OC'able K CPU for that Z170 motherboard, it seems like a lot of untapped potential left for that build.

    "With that done, I’ve simply boosted the CPU base clock and DRAM frequencies, and added that extra 0.35V in the CPU voltage settings. Since I have mentioned voltage twice now and it is making me nervous, please note that neither I nor PCGamesN are responsible for you frying your hardware by changing those settings. This, and whatever fire you start, is on you."

    Comforting Words... :rolleyes:

    That reminds me of this cool hack, putting a Suzuki Hayabusa Hyperbike Engine in an Austin Mini Cooper :)

    He put a HAYABUSA Motor in his MINI - It’s SICK!


    I preferred my Hayabusa Engine in it's original skins, up to 180 MPH :confused::eek::D

    Suzuki Hayabusa GSX1300R - Acceleration 0-300km/h & Startup & Exhaust Sound & Burnout & Dyno
     
    Last edited: Nov 22, 2017
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  9. Danishblunt

    Danishblunt Notebook Virtuoso

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    Thanks for your post, very useful!

    So even older haswell HQ CPU's are limitless when doing a microcode update. With a mod on the heatsink I'm sure u could somewhat get temps more "proper", but then again, stresstest makes the CPU way hotter than "normal" use anyways, so I'm sure your temps on gaming and stuff are rather low.
     
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  10. Papusan

    Papusan BGABOOKS = That sucks!! STAHP! Dont buy FILTH...

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    I didn't know Dell got own special designed unlocked Core i7 BGA versions from Intel for use in their notebooks. Damn, nice... 7820hk Extreme Edition and Intel® Turbo Boost Max Technology 3.0:D
    upload_2017-11-22_12-56-16.png

    And I didn't know Core i5 processors come with Intel® Turbo Boost Max Technology 3.0. I really need to step up and read me up more on newer tech:)
    upload_2017-11-22_12-59-20.png
     
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