The ASUS Zephyrus S is a thin gaming laptop with some nice specs, but how hot does it
get and is there any throttling? In this video I’ll perform some detailed thermal testing
and find out how overclocking and undervolting can help improve performance and temperatures.
In my configuration here I’ve got the Intel i7-8750H CPU with Nvidia GTX 1060 graphics,
so expect different results with the 1070 Max-Q version.
Thermal testing was completed with an ambient room temperature of 22 degrees Celsius, so
expect warmer temperatures in a warmer environment. Also keep in mind there are heatpipes shared
between processor and graphics, so a change in one component may affect the other.
Like other ASUS laptops, this one also lets you pick between silent, balanced, and turbo
modes. These are built in profiles that increase performance at the cost of boosting fan speed
and CPU TDP, and I’ve done my testing with all three.
Starting at the bottom of the graph, at idle the temperatures are fairly cool with silent
mode, shown by the light blue bars. The gaming tests were done with Watch Dogs 2, as I find
that to use a good combination of CPU and GPU. Continuing up in the green bar with balanced
mode the temperatures are fine. Once turbo mode is enabled the CPU temperatures increase
by 5 degrees Celsius as the power limit increase allows it to perform better and run hotter
as a result, shown by the yellow bar. Once the CPU is undervolted by -0.150v the temperatures
drop back a little, both on the CPU and graphics, shown by the orange and red bars.
The stress tests were done by running Aida64 and the Heaven benchmark at the same time
in order to attempt to fully utilize both the processor and graphics. Moving up in the
graph and continuing with the dark red bar with balanced mode we’re still getting around
the same temperatures. Again with turbo mode enabled the temperature on the CPU rises as
it’s able to run at higher speeds, which we’ll see in the next graph, and then a
pretty similar story with the -0.150v CPU undervolt applied in purple and dark blue
at the top.
These are the average clock speeds for the same tests just shown. Again starting down
the bottom we can see that the CPU undervolt raises the average CPU clock speed by around
400MHz. We also see an improvement to the graphics clock speed every time turbo mode
is used, as it applies a 100MHz overclock, but as we saw in the last graph this didn’t
really affect GPU temperatures. Even in balanced mode with the CPU undervolt, shown in orange,
we can get better CPU performance compared to using turbo mode, and then full performance
with the turbo profile and undervolt combined, shown in red. It was a similar story with
the stress tests, although slightly more power limit throttling in this worst case scenario
prevented us reaching the full 3.9GHz all core turbo speed of the i7-8750H.
These are the clock speeds I got while just running CPU only stress tests without any
GPU load. As mentioned, there are three built in profiles on the laptop called silent, balanced,
and turbo. With the Aida64 stress test running, I was actually getting lower clock speeds
with the undervolt applied with the silent profile. With the balanced profile there was
still power limit throttling with this stress test, but with the undervolt applied in red
we were able to get full performance. Even with the turbo profile we still weren’t
quite able to get full CPU performance, shown in purple, until we apply the undervolt, shown
at the top in dark blue.
To demonstrate how this translates into performance I’ve got some Cinebench CPU benchmarks here,
with the older 7th gen i7-7700HQ just down the bottom for comparison. The results are
close to what we saw with the CPU only clock speeds just shown, and interestingly in silent
mode single core performance does appear to be negatively affected. Full performance in
multicore seems possible with both turbo mode enabled with the CPU undervolted.
Here are the GPU only clock speeds while under a graphical only stress test, at stock with
the balanced profile, and then with the 100MHz overclock from the turbo profile in green,
and then with a manual 200MHz overclock shown in red.
So how does this performance boost actually translate into games? I’ve tested with the
exact same Windows, Nvidia and game updates installed, the only changes were the ones
listed here.
Far Cry 5 was tested using the built in benchmark, the average frame rates at ultra settings
were 3.6% better compared to stock speeds, and a 3.9% improvement to 1% low, so we are
able to get a little performance boost from this, though results will of course vary between
games.
As for the external temperatures where you’ll actually be putting your hands, at idle it
was in the low 30s. With the stress tests running the keyboard area was alright, getting
to the high 30s, and then into the 50s up the back, and then similar results while gaming,
which is perfectly fine as you won’t be putting your hands up the back anyway.
As for the fan noise produced by the laptop, I’ll let you have a listen to some of these
tests.
At idle with the silent profile enabled the fan was quiet but still audible. While gaming
and under stress test it was about the same, and around the same volume as most other gaming
laptops I’ve tested, and then fairly loud with turbo mode enabled and the fans maxed
out.
Overall the performance was pretty good for an 8th gen i7-8750H laptop, even in these
worst case scenarios the temperatures didn’t really get that high, low 80s at the worst.
While under a combined CPU and GPU stress test the CPU would not pass a 35 Watt TDP,
but turbo mode would increase this to 45 Watts.
As this is the lower specced version of the Zephyrus S the results shown here aren’t
worst case, I’d expect the 1070 Max-Q to possibly be a little warmer, but from what
we’ve seen here it does appear to have thermal headroom available.
These differences in performance shown aren’t hard and fast rules, there are different factors
which will vary results, primarily the temperature of the room you’re running in, application
of thermal paste, and even the specific hardware which comes down to the silicon lottery. You
may not be able to undervolt or overclock your hardware the same as me, it depends on
the chip and its specific power requirements, so don’t just blindly copy my settings and
do some testing to find out where your stable point is for best results.
While you could improve the temperatures by swapping out the thermal paste, that’s not
something I can test in a review unit. If I go ahead and remove the stock thermal paste
and replace my own, I can't put the old paste back, so the next reviewer would experience
something different from what you'd actually see with the product and unknowingly report
incorrect information due to what I’ve done.
Undervolting and raising the fan speed on the other hand aren’t physically intrusive,
and as we've seen it did improve temperatures and gaming performance a little in this particular
unit with no downside once you’ve got a stable undervolt.
Let me know how much of a performance boost you’ve found by undervolting your hardware
and what you thought of the improvements here, and don’t forget to subscribe for the full
review of the ASUS Zephyrus S gaming laptop, as well as future tech videos like this one.