I recently reviewed the Gigabyte Aero 15x laptop, and in my thermal testing I noted
some throttling issues that I had with my review unit.
Some other reviews I've since watched didn't seem to have this issue, while others in the
comments noted they’d had even worse overheating issues, I wasn’t sure if it was just my
particular unit.
Some of you wanted to see if this could be improved by undervolting the CPU, so let's
find out.
This laptop has Intel's new 8th generation Coffee Lake 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.
As I mentioned in the full review, while gaming the CPU would often sit at around 2.9GHz to
3.1GHz on all cores, it would vary depending on the game.
Basically it wasn't boosting as high as it could due to thermal throttling, even with
the fans fully maxed out performance was being lost while the CPU consistently sat at 90
degrees celsius.
While running a full CPU and GPU load with the Aida64 and Heaven benchmark at the same
time the cores also sat at 2.9GHz at 90 degrees celsius.
The throttling only seemed to happen under both a CPU and GPU load, if I ran a CPU only
stress test such as Aida64 with no GPU benchmark going at the same time, no CPU throttling
occurred.
By undervolting the CPU, we're essentially telling the CPU to use less power to perform
the same tasks, and less power results in less heat.
This is the first time I've tried it, and it was quite simple using Intel's Extreme
Tuning Utility, also known as XTU.
Put simply you slowly decrease the core voltage level, run a stress test to confirm stability,
then once confirmed to be stable drop the voltage some more and repeat until you've
got a stable system.
If you take it too far you'll blue screen in Windows if the CPU isn't getting enough
power.
In my case I was able to reduce the CPU core voltage by 0.160 volts and had no stability
issues, in my Aida64 and Heaven stress test there was still a little throttling, the CPU
was sitting at 90 degrees celsius again however the 6 cores were boosting between 3.7 and
3.9GHz, so much better than the 2.9GHz previously.
While playing Watchdogs 2 at ultra settings there were no issues at all, the CPU was now
running at the maximum 3.9GHz speed on all cores, even with the GPU overclocked and it
was still running cooler, at around 85 degrees as shown here, so not only are we getting
full speeds, the temperatures are lower too.
Great, so how does this performance boost actually translate to games and practical
applications?
I'll be focussing on games here, as mentioned earlier I didn't actually have any throttling
with a CPU only workload, it only happened when both the CPU and GPU were in use at the
same time, as I guess that was just too much for the cooling solution to handle.
In the games tested the exact same Windows updates and Nvidia drivers were installed
that I used in the full review benchmarks, which I’m showing here as the default results.
I haven’t re-tested every single game due to time constraints, as I’ve got to send
the laptop back.
In Rise of the Tomb Raider with the built in benchmark we’re seeing just a 4% improvement
while undervolting compared against running at default.
In the Witcher 3 there’s basically no difference at max settings, and the undervolted CPU results
move ahead as we get lower, on average we’re getting a 2.8% boost with undervolting.
In Shadow of War with the built in benchmark we’re getting a 2.3% improvement on ultra
settings and then again this improves as we step down in settings, averaging about 3.5%
of an improvement while undervolted overall.
PUBG is a bit strange, I was seeing slightly better results prior to undervolting at higher
settings, which doesn’t really make sense to me.
I was testing with the same replay so there shouldn’t be any differences between each
run, the undervolted cpu takes the lead at the lower levels though.
In Ghost Recon I’ve used the built in benchmark again, and at ultra settings the undervolted
CPU is performing 6.6% better, while at minimum settings this increases all the way up to
a 15% improvement.
Averaging all setting levels in this game, undervolting is giving us a 9.6% performance
boost, the most so far.
In 3DMark we’re not really seeing much difference in Timespy, just a 1.4% boost with undervolting
and 3.3% of an increase in Firestrike.
As shown the improvement in CPU clock speed does seem to translate to slightly better
gaming performance, nothing spectacular, though it depends on the game.
We tend to see a larger boost in performance at the lower setting levels, which makes sense
as with lower graphical settings you're more likely to be CPU limited as there's less work
for the GPU to actually do, whereas at the higher setting levels the GPU is able to stretch
its legs, so the gap closes a bit more.
On average with all of these tests at all setting levels we’re seeing a 3.79% performance
improvement with the undervolt applied, but keep in mind this is an average, the results
seem to vary more at lower settings as mentioned and then again between games.
These differences in performance shown aren’t hard and fast rules, as mentioned some people
didn’t notice thermal throttling at all with their Aero 15x, while in other cases
some people experienced worse.
I presume the individual CPUs would also have different limits with regards to the amount
of voltage required to run, so just using my numbers with your own laptop probably isn’t
a good idea.
I guess what I’m trying to say here is that results may vary based on a number of different
factors, but if you’re experiencing thermal throttling then attempting undervolting could
give you a performance improvement.
Replacing the thermal paste is another option to try and improve this issue, but it’s
not really something I can do with a review unit for a number of reasons.
Generally, a company won't really want you to tamper with the laptop as it 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 really put
the old paste back, so the next reviewer would experience something different from what you'd
actually see with the product.
Undervolting on the other hand isn't physically intrusive, and as we've seen it did improve
the performance in this particular unit, specifically in Watchdogs 2 at ultra settings we went from
2.9GHz at 90 degrees to 3.9GHz at 85 degrees, so going forward I'll look to also include
the results of undervolting in my laptop reviews if there’s thermal throttling present, as
realistically it’s a great way to get back some of your performance if you’re running
too hot.
Perhaps it makes sense to cover that information in more detail in a separate video like this
one instead?
Let me know what you guys think, and I’d be interested in hearing your experiences
with undervolting, and how much of an improvement you’ve seen, or alternatively if you’ve
had any problems from doing it, let me know down in the comments, and don’t forget to
subscribe for future tech videos like this one.