Lenovo Legion Y740 17" 15"

Discussion in 'Lenovo' started by victorgm, Jan 30, 2019.

  1. Gimmy

    Gimmy Notebook Enthusiast

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    I did try to take the screws out for thermal re-paste, y740. Few months back. Those black screws are very very delicate, not sure why Lenovo even use them. A wrong bit and you are done. Just like yours I got mine rounded (stripped badly). I tried many different things, mostly all I came across online. Rubber band method, using quick glue, screw extractor, moody tools screw extractor, another extractor set from Menard, precision screwdriver sets, and lastly reverse drill method. Nothing helped at all, all failed for me. That bit** stripped screw is still there hiding under the back panel. Good luck to you. If you ever can take that stripped screw out, I appreciate if you let me know how. Hope someone may have better suggestion on this. :(
     
  2. kotomikun

    kotomikun Notebook Enthusiast

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    Even in the CPU test part of Time Spy? At 3.5 Ghz, my CPU usually stays under 80 until that part, where it hits 90+. Have to put it all the way down to 3.0 Ghz to keep it under 80 the whole way through. It still gets an above-average overall score with the GPU overclocked (had previously just used the overclock-scan result, tried flattening the curve at ~1800 MHz and it got the same score, so that part seems to work; this is with a 2060 though and I wasn't paying attention to GPU temps since that hasn't been an issue for me, it rarely goes over 70 C) but this processor continues to be a bit of a disappointment.

    Did those tests in performance fan mode (which does seem to make a difference in scores, though not temps). CPU is also limited to 45 watts for short-boost, though I don't think it gets that high anyway with those clock speed limits.
     
  3. TheRealHendrix

    TheRealHendrix Notebook Enthusiast

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    When I run benchmarks like Fire Strike/Time Spy, I usually keep my 9750H running at 4.0Ghz if I'm looking to get the highest score possible. I usually don't run into any temperature issues with synthetic benchmarks though. Gaming always gives me much higher temps. With a 150mv Undervolt applied and the back of the laptop raised 1-2 inches with a stand, I don't ever see thermal throttling, whether my CPU is running at 4.0Ghz or underclocked. Do you have the back of your laptop raised up? It makes a huge difference. What kind of temps do you get when gaming compared to the benchmarks?

    The thing about the Undervolt is you can apply a higher Overclock than what the scan gives you and still be stable. Even if say +200 isn't normally stable for you, if you undervolt you can reach a higher OC on the parts of the curve that are left of the flatline. At least this has been my experience. I usually can't go past +150 core OC. But when I Undervolt at 1,785Mhz @793mv, I can apply a +200 core OC and it's stable. So the points to the left of the flatline are OC'd higher than what's possible without the undervolt.

    Undervolting only seems to lower the GPU temps by maybe 3-5c. But, this also leads to lower CPU temps because they share a heatpipe. And also when the GPU runs cooler, due to the way GPU boost works it will run at higher clock speeds at the same voltages. As GPU temps get higher GPU Boost lowers clock speeds by moving the v/f curve downwards. When it runs cooler it keeps the voltage/frequency curve higher. Hopefully this helps clarify some things.
     
  4. kotomikun

    kotomikun Notebook Enthusiast

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    Jeez. I guess that settles it--need to call Lenovo tomorrow and see if my warranty is worth anything. Wish I could have figured this out before the end of my return window, but if it's defective it shouldn't matter.

    I do have the back lifted up a couple of inches, but this has little to no effect. Don't really have any super-demanding games to test with at the moment, apparently, since 3DMark is harder on it than anything else, but even older games get the CPU pretty hot unless it's underclocked/underwatted/whatever. Cinebench or any other CPU-only-stresser makes it hit 94C thermal throttle more or less immediately on stock settings (which doesn't make the temperature go down, only keeps it from climbing even higher).
     
  5. TheRealHendrix

    TheRealHendrix Notebook Enthusiast

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    Do you have an undervolt applied to your CPU? those temps do sound too high, even at stock settings. I didn't really test mine too much at stock settings but I know I did get thermal throttling without an undervolt and on a flat wooden desk. Once I applied a 150mv UV though and kept the back raised, it got rid of the thermal throttling for me. I still saw max temps in the high 80s though occasionally during spikes. Once I underclock though it pretty much keeps my CPU temps out of the 80s. Still hits maybe 80-82c running at 3.6Ghz during spikes, but that's just before the fans rev up to max under a heavy gaming load.
     
  6. kotomikun

    kotomikun Notebook Enthusiast

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    It has a cache+core undervolt of 140mv, yes. Even with that, raised back, and reducing the turbo power limit to 45 watts, just running Cinebench makes it hit 90+. Not on every core, though--a couple of them stay below 80 no matter what I throw at them. Seems like some sort of heatsink issue based on what others have said.

    Lenovo support, somewhat to my surprise, agreed that those temps are too high and said they'd send someone out (likely in a week or so) to attempt a fix (replacing the motherboard, probably), so we'll see how that goes.
     
  7. TheRealHendrix

    TheRealHendrix Notebook Enthusiast

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    Yeah that definitely sounds like either an uneven heatsink or bad factory thermal paste job. Hopefully they come out and fix it for you. Motherboard replacement will definitely solve the issue I'd imagine.
     
  8. kfxsti

    kfxsti Notebook Evangelist

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    @codeHusky
    Nerve Sense on bios 1.03 is working with Extreme Cooling . I will test 1.06 tomorrow. and i will see if i can get the OC features enabled on both or either.
     

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  9. Sacks

    Sacks Newbie

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    Tested with 8th gen. Worked on bios 1.08 that has the fn+q function on default. On 1.10 with the fan profiles, didnt work. The nerve sense just lost the option alltogether... Dissapointing
     
  10. bryanryan

    bryanryan Notebook Enthusiast

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    15" is finally available on UK site
     
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