IdeaPad Y700-15ACZ Review

Discussion in 'Lenovo' started by Assembler, Oct 25, 2015.

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  1. Apollo13

    Apollo13 100% 16:10 Screens

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    I was going to ask, how powerful is the power supply? Particularly the battery-draining-while-under-heavy-CPU-and-GPU-load sounds like a too-weak-power-supply problem to me. That really shouldn't happen if it has an adequate power supply, including on a notebook with a dGPU.

    All in all it sounds like it would have been quite good if the cooling and/or power supply were better. Can't really fault them for setting 85 Celsius as the thermal limit, as that is pretty hot for a laptop, but if they're selling it with that GPU, it should be able to cool it enough to keep everything running at no less than stock clocks indefinitely.
     
  2. Assembler

    Assembler Notebook Consultant

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    The same 135W power supply used by the Y50 (20V, 6.75A). The system should act more "smart" if one component hits the thermal limit, like reducing the CPU a few hundred MHz when reaching 85° C and back to its base clock when reaching 90°. They just implemented the handbrake method slowing down the CPU as much as possible, otherwise i would have never noticed this kind of behaviour.

    I removed the stock thermal compound of the heatsink and applied some good old ArticSilver, temps are slightly better now but CPU with turbo + GPU still results in throttling. I will contact Lenovo and see if they are aware of this.
     
    Last edited: Nov 13, 2015
  3. Maru

    Maru Notebook Consultant

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    If the fan intakes air from the bottom, does elevating the back of the notebook to improve airflow make a difference?

    To state the obvious: for buyers that require long sessions without throttling (e.g., not 10min short rendering sessions but 25min long intense game sessions), if it turns out the cooling system cannot keep sustained sessions with the FX-8800P and R9 M385X going without eventually throttling, apparently the choices are either to (a) back down to lower power, lower detail settings in apps and games, or (b) hope some external cooling or airflow assistance works for this laptop, or (c) choose lower power, lower performance components, such as the Y700 with A10-8700 and R9 M380 (Newegg).
     
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  4. Assembler

    Assembler Notebook Consultant

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    I didn't try that so far, possibly it would decrease temps slightly but not enough to prevent throttling.

    The options to lower power are limited, no software i checked was able to reduce core clock and/or voltages of the CPU/GPU. Reducing video settings to a point where the min. FPS (while throttling) are still playable is not really what you want. In this case you could buy another machine with slower components that manages to cool them properly.

    After a long and pointless discussion with the Lenovo support they gave me an appointment for one of their service center. Its still there for a complete checkup, i am waiting for a call now.
     
  5. Narao

    Narao Newbie

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    So I've been looking at all of the carrizo laptops that have been coming out and seeing if there was anything that was tempting to purchase. Last monday this laptop was on sale for $799.00 at best buy so I picked it up. I had a lenovo y410p previously and new all too well about some of the downfalls to the Y-series. I was impressed by how much the build quality and especially screen quality had improved. I'm actually pretty happy with it so far, but I also noticed some stuttering while trying to play Battlefield 4 and Star Wars: Battlefront. After digging around and playing with some settings, I can play with most settings on ultra (minus some obvious ones like AA and post processing) at a comfortable 45-50fps.

    The Problem that found is this is peppy processor but it can be pushed too far if you let it. I was noticing stuttering even before the laptop got warmed up, so I ruled out thermal issues and started looking into power issues (i.e. amps), and when this little processor turns on turbo core and boosts up to 3.7 ghz, it draws more power and heats up pretty good. If you go into your advanced power settings and look at the processor power management, turn down the maximum from 100% to 99% and it won't use turbo core, heat up your machine, and cause a whole lot of issues.

    I did run cinebench after doing this and the numbers weren't as nice as yours, but it runs a lot cooler and is consistent.

    As for the battery discharging while playing games, I didn't have any evidence of that behavior, even while I had turbo core enabled.

    I actually think this is a pretty decent laptop for the price. It's not the monster gaming machine that a lot of people think they need, but it isn't a slouch either. I hope you hear good new from the shop and they can get things squared away.
     
  6. mikel0181

    mikel0181 Newbie

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    y700 15 touch Intel edition also throttles, but way more on the GPU. At least with the intel one we can control CPU with using XTU. But the GPU throttles back from a low power limit
     
  7. Assembler

    Assembler Notebook Consultant

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    This has the same effect than limiting the CPU power in CCC to 85%, it will run with constant 1.8 GHz (300 below base clock) instead of the max 3.4 GHz turbo. Even this setting is not stable, as the GPU will still overheat if you didn't change the thermal compound on the heatsink. You won't notice it because 1.4 GHz vs. 1.8 GHz is not much different in terms of speed. If you compare this to frame rates with the max. turbo you will loose 50%+ fps... that is not acceptable (at least for me).

    To see if you battery discharges.. first charge it to 100% than activate the "Battery Conservation Mode" in Lenovo Utility that will prevent recharging until 55%. Now play your game of choice and track the charging level.

    Yeah i thought that the Intel version will have similar issues. TDP specs are more or less the same:

    AMD: 35W CPU / ~85W GPU
    Intel: 42W CPU / ~75W GPU

    Probably the CPU on the Intel version is reducing turbo speed or even falls back to base clock before overheating so mostly the GPU will throttle. The AMD version will run with its full speed until overheating. The whole cooling system is not well designed.
     
    Last edited: Dec 3, 2015
  8. splashy

    splashy Notebook Consultant

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    Thanks for the review. I didn't know you can get this laptop ahead of time in China

    About the gaming performance - please try DX12 games like Ashes of Singularity !
     
  9. monstercameron

    monstercameron Notebook Enthusiast

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  10. Assembler

    Assembler Notebook Consultant

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    Still running Win8.1, maybe Narao can test some DX12 games/benchmarks.

    I just checked the latest Lenovo driver for Win8.1 and the Crimson Edition. The old CCC does not show the option to enable FreeSync and the Crimson driver says "Not supported". I guess we will have to wait for a new driver to enable FreeSync.
     
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