I've currently got the Razer Blade 2018 gaming laptop for testing, and as a thin and powerful
laptop I wanted to test the thermal performance to see what amount of throttling would be
experienced, so let’s take a closer look and find out if we can improve things with
some undervolting.
This laptop has Intel's new 8th generation Coffee Lake i7-8750H CPU, which has 6 cores
with 12 threads. It's clocked at 2.2GHz, but the single core turbo boost speed is 4.1GHz,
while the all core boost speed is 3.9GHz so it will get quite hot with all that power,
especially in a laptop this thin, given I’ve seen throttling in even larger laptops that
I’ve tested.
I’ve also got Nvidia 1070 Max-Q graphics in this model, so expect different results
with the 1060 Max-Q version.
I’ve tested all games with gaming mode enabled, basically Razer’s Synapse software lets
you toggle between balanced mode and gaming mode, where gaming mode will increase the
CPU power limit, undervolt the graphics and overclock the graphics a bit for better performance,
which also results in more heat.
Thermal testing was completed with an ambient room temperature of 18 degrees celcius, it’s
cold here at the moment as it’s winter in Australia, so expect warmer temperatures in
a warmer environment.
At idle the CPU and GPU were on the warmer side, above 50 degrees celsius. While playing
PUBG at high settings we can see that the temperatures rose as shown in green. By undervolting
the CPU by -0.140v as shown in yellow we can reduce the temperature of the CPU a little.
The graphics were maxed out at 90 degrees regardless of the test, this was a combination
of power limit and thermal throttling.
The full load stress tests were run using Aida64 and the Heaven benchmark at the same
time, and I’ve tested both the balanced mode and gaming mode here. In balanced mode
the CPU gets a lower power limit, so performs less, as we’ll see in the next graph, but
temperatures improve a little with the undervolt applied in red.
These are the average clock speeds while running the same tests for the temperatures just shown,
it wasn’t possible to reach the full 3.9GHz all core turbo clock speed in any of these
tests, which in the case of the stress tests was due to power limit or thermal throttling,
granted in PUBG I don’t think the CPU needs to max out as it’s not a bottleneck, which
probably explains the lower clock speeds while undervolted in yellow, it just doesn’t really
matter, maybe I should be using a different game for this test but these are the speeds
that I saw.
With the gaming mode enabled the TDP increased, so it seems like this affects the power limit
provided to the CPU, I wasn’t able to otherwise tweak it in Intel XTU. This explains why the
clock speeds rise with gaming mode enabled, giving us more power but also a hotter system
as we saw in the last graph. Undervolting in red and dark blue did improve things too,
but still not quite enough to fully remove throttling in this particular stress test,
but this will of course differ based on the specific workload.
Great, so how does this performance boost actually translate to games and applications?
In the games tested the exact same Windows updates, game updates and Nvidia drivers were
installed so there shouldn’t be any changes other than the CPU undervolting.
In CS:GO for the most part we’re actually seeing slightly lower 1% lows with the undervolt
applied, but slightly higher average frame rates.
Ghost Recon was tested with the built in benchmark, and the results are pretty close together
for the most part, but the difference becomes slightly larger at the higher setting levels.
Far Cry 5 was also tested with the built in benchmark, and the results are a mixed bag,
lower 1% lows at all settings while the averages vary a little.
Ashes of the Singularity was tested as more of a CPU demanding game, and we’re seeing
a larger difference at the lower settings on average, but overall there is a small improvement.
As shown the improvement in CPU thermals and power does seem to translate to slightly better
gaming performance, nothing major, though it of course greatly depends on the game,
some games like Farcry 5 for instance didn’t seem to make a difference, whereas more CPU
intensive ones like Ashes of the Singularity received a clear boost.
Typically most games depend more on the graphics more than the CPU though, so realistically
in many cases I don’t think you’ll see big gains from CPU undervolting here. For
that reason in general we’re not seeing much of a difference in the games tested,
whereas CPU intensive applications should see a larger gain.
These are the clock speeds I got while just running CPU only stress tests without any
GPU load, and even with no GPU load we’re still seeing power limit throttling preventing
the full 3.9GHz speed, but gaming mode and undervolting did help raise this.
I’ve got some Cinebench CPU benchmarks here, and we can see that there’s a fair difference
in performance just by going from the balanced to gaming mode, and we can improve this further
with the -0.140v undervolt. Despite this I was still seeing power limit throttling as
discussed earlier in the CPU only stress test, the 8750H should be able to pass 1200 in ideal
circumstances, but it’s not too far behind here so we’re almost able to get full CPU
performance in this CPU only workload.
As for the external temperatures where you’ll actually be putting your hands, at idle the
body of the laptop is sitting in the mid 30s in the center and getting warmer towards the
back. While gaming this increases to the 50s in the center and was a little warm to the
touch, although the left and right sides were quite cool in comparison, with very similar
results in the full load stress test.
As for the fan noise produced by the laptop, I’ll let you have a listen to some of these
tests.
At idle it was still audible, which was expected based on the warmer idle temperatures, and
then while gaming and with the fans maxed out it wasn’t too different from many other
laptops I’ve tested, still a bit loud though. Balanced mode was a little quieter than gaming
mode, as we saw before it gets hotter in gaming mode. I didn’t test temperatures for both
default fans and manually maxing out the fans, as in gaming mode while playing games or under
stress test I found the fans to be maxed out the same regardless which would give the same
results.
As for overclocking, the 8750H CPU can’t be overclocked, but I was able to increase
the GPU core clock of the Max-Q 1070 a little on top of what gaming mode set. These are
the average speeds while running the Heaven benchmark in the default balanced mode, with
gaming mode which essentially overclocks the graphics by 100MHz on the core and 300MHz
on the memory, and then with my manual overclock we get just a little extra, but not much,
gaming modes already doing a pretty good job.
I’ve retested PUBG with both balanced and gaming modes, and then with the gaming mode
undervolted and we’re just seeing small differences in performance between them. I’ll
also note that I haven’t tried manual GPU undervolting here as gaming mode in the Razer
Synapse software has already done this quite well.
These differences in performance shown aren’t hard and fast rules, there are different factors
which will vary results, primarily the temperature 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 your 8750H the same as me, it depends on the chip and it’s 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.
I’m not sure how practical it would be to replace thermal paste in this model, as it
uses a vapor chamber cooler which takes up quite a bit of space. Presumably this could
be removed and paste is used between it and the CPU and GPU, but this isn’t really something
I can test with a review unit for a number of reasons.
Generally I can’t really tamper with a review unit, the laptop needs to work in the same
way for the next person to receive it. 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 on the other hand isn't physically intrusive, and as we've seen it did improve
the performance and temperatures in this particular unit with no downside once you’ve got a
stable undervolt. It’s a great way to get back some performance if you’re running
too hot or facing power limit throttling.
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 Razer Blade 2018 gaming laptop as well as future tech videos like this one.