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snake2332
Token Ring
Posts: 159
Registered: ‎04-07-2014
Location: US
Views: 5,473
Message 1 of 4

Yoga 720 15" - Re-pasting the CPU & GPU yields good results!

I love this Yoga 720 15" machine, but the temperatures were uncomfortably high and required turbo-boost to be disabled to keep it from throttling a lot. Supposedly Lenovo disabled turbo-boost from the factory, limiting the CPU to 2.8GHz, but with my machine turbo-boost was enabled when I first launched ThrottleStop. Notice how they don't advertise the CPU as 3.4Ghz, or boosting at all. I've seen that the XPS has this problem, too, and people have had success by re-pasting the thermal grease/compound/TIM on the CPU and GPU with a quality product. I'm surprised that Dell and Lenovo both skimp in this area and use poor quality compound in a compact and high powered machine. They could spend a dollar more per laptop and we'd all be much better off.

 

I decided to use Thermal Grizzly Kryonaut, one of the highest rated compounds. I didn't want to get into the liquid metal stuff, like the OWNorDISOWN guy on youtube, for various reasons. Before the re-paste, I ran some benchmarks with turbo on, turbo off, and undervolting the CPU core, cache and IntelGPU. Then I ran them after the re-paste, recording ambient temperature since it was fluctuating enough to matter. The results are in this publicly-shared spreadsheet, and here's a screenshot of it (all temps are in celcius and the colored columns are "after repasting "(AR)):
Re-paste spreadsheet Yoga 720.jpg

 

Two results from the testing don't make complete sense to me, lines 10 and 13 (testing with turbo disabled). The GPU performed quite a bit worse after re-paste even though CPU & GPU temps were much cooler. Not sure why that would happen, hopefully that doesn't reflect how games will perform. The GPU scores also went way down when compared to the same "after re-paste" test that had turbo enabled (lines 8 and 11). Turbo shouldn't affect the GPU score very much, if at all, yet it did. Maybe just an anomaly and I need to test more...or just move on because it's just a benchmark.

 

The re-paste has basically made it so I can enable turbo-boost permanently and not have to worry about it hitting 100*C (I would do the alt+0176 command for a degrees symbol, but you know...no 10-key). The hottest I could get it to hit was 90*C on one core. I need to do some more testing in games, like GTA V and PUB-G, since those games both pushed the CPU almost to its limit, like 93 to 96 degrees, while the GPU is around 91, and that's with turbo-boost OFF and under-volted. I imagine I can play both of these games now and stay in the 80's for temps, with turbo enabled. I will report back when/if I do more testing. By the way, under-volting seems to make zero difference in my testing, like it's not working or something. I wasn't monitoring the voltage or watts while benching, so I don't really know.

 

I believe the reason the GPU raised in temperature on some benchmarks is because the CPU was getting worked hard while the GPU wasn't, and the better TIM caused the GPU to absorb more heat from the shared-with-CPU heatpipes. With worse TIM, the GPU wouldn't suck down or absorb as much heat from that shared heatpipe, and the GPU wasn't working hard so it wasn't producing much of its own heat. I also believe this explains the results from the OWNorDISOWN video, where he was blaming the Aeronaut TIM for the GPU being hotter in his tests. Pretty much all of the benchmarks where the GPU was being used heavily show a drop in temps after the re-paste.

 

This guy also repasted his, but gave no numbers or scientific data, just says that the fans seem quieter or something.

 

Overall, I'm very satisfied with the results, and am happy with the Yoga. The last nagging issue is the need for dual QHD external monitors through a dock, but I have high hopes for daisy-chaining from one of the Lenovo docks.

 20170714_022915.jpgGlad I had a T5 torx driver from a cheap toolkit that I got to fix a Galaxy S4. Also note the battery is disconnected because that would suck to hit the power button while working on it. Also note I was a good boy and used an ESD wrist strap, but did I clamp it to a good location?

20170714_023057.jpgYes it's copper and you could use liquid metal.20170714_023437.jpgGetting ready to spread. I needed to add a little more than this to get good coverage.

snake2332
Token Ring
Posts: 159
Registered: ‎04-07-2014
Location: US
Views: 5,363
Message 2 of 4

Re: Yoga 720 15" - Re-pasting the CPU & GPU yields good results!

Also wanted to pipe in with some results from testing temperatures with a "protective decal skin" applied to the bottom, deck (palm rest and area around keyboard), and top of the lid. I read that decals shouldn't affect temperatures much, as they aren't thick enough to worry about. The decal I got is possibly thicker than others since it has a rough brushed aluminum texture to it. 

 

I updated the linked spreadsheet with results of my testing. Basically, it doesn't seem to affect the temps. Some tests showed a 2*C increase, some showed a decrease. One test had an 8*C decrease for no known reason. I would conclude that the skin isn't making it hotter, though my testing shows there is a lot of variance possible in temps, and it's kind of hard to conclude either way.

 

I will attach some pics taken with my S7Edge. I plan on taking a hair-dryer to it still to smooth out some bubbles or creases that exist. I kind of messed up in a few spots and creased, stretched, or damaged the decal. I'll be more careful with the next one I get. Also, I quickly removed the touch-pad piece and the narrow strip under the display. I only installed those for testing and picture-taking purposes, as I knew they were both bad. I also might remove the bottom skin (not pictured).

20170717_190236.jpg20170717_190409.jpg

EDITED: Removed the other night-time pics and inserted a few from the next morning, still need to take a hair dryer to it.

YogaDecalrusDeck.jpgYogaDecalrusEdge.jpgI put a strip on the edge to protect it while in tent pose.YogaDecalrusTouchpad.jpgClose enough of a color match.20170718_111405.jpgNo flash, somewhat over-exposed.YogaDecalrusLidFlashOn.jpgWith flash, appears darker than it really is.

snake2332
Token Ring
Posts: 159
Registered: ‎04-07-2014
Location: US
Views: 5,331
Message 3 of 4

Re: Yoga 720 15" - Re-pasting the CPU & GPU yields good results!


The re-paste has basically made it so I can enable turbo-boost permanently and not have to worry about it hitting 100*C (I would do the alt+0176 command for a degrees symbol, but you know...no 10-key). The hottest I could get it to hit was 90*C on one core. I need to do some more testing in games, like GTA V and PUB-G, since those games both pushed the CPU almost to its limit, like 93 to 96 degrees, while the GPU is around 91, and that's with turbo-boost OFF and under-volted. I imagine I can play both of these games now and stay in the 80's for temps, with turbo enabled. I will report back when/if I do more testing. By the way, under-volting seems to make zero difference in my testing, like it's not working or something. I wasn't monitoring the voltage or watts while benching, so I don't really know.

 

 

UPDATE: GTA5 and PUB-G can still make the CPU hit 100*C with turbo enabled. With turbo disabled, it still reaches around 90*C when my ambient temp was 77*F (25*C). Still much better than before. These games are pretty demanding, so I expect most of the other games I play to be easier on it. I just tried Skyrim Special Edition 1080p high with TAA and it hit around 87*C CPU and 79*C GPU with turbo enabled, though ambient temp is only 67*F (19.44*C).

 

StGemma
Fanfold Paper
Posts: 10
Registered: ‎03-06-2018
Location: US
Views: 3,404
Message 4 of 4

Re: Yoga 720 15" - Re-pasting the CPU & GPU yields good results!

Hello, does repasting the thermal paste break warranty? Also, where did you get the protective decal skin, and how much did it cost? Thank you!

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