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 post like this one instead? Let me know what you guys think!