Intel, what HAPPENED? Core i5 vs i7 Laptop Performance

If you are currently in the market looking to buy a thin-and-light laptop chances you are just bombarded with a lot of options from different manufacturers with both Intel and AMD processors. AMD just recently announced their Ryzen 5000 H-series of CPU’s for gaming laptops and the 5000 U-series for thin-and-light devices. But the problem is that there isn’t a single laptop that ships with a Ryzen 5 U-series or a Ryzen 7 U-series CPU, at least at the time I’m writing this article. On the other hand, the 4000 U-series are still really awesome options that pretty much dominate everything that Intel has to offer in their CPU lineup for thin-and-light devices.

Now their latest offering is Tiger Lake, and we have covered a few laptops with those already. At this point, the Core i5-1135G7 and the Core i7-1165G7 are by far the most popular options, but with both being based on a 4-core/8-thread layout you might be asking yourselves, which one should I pick? And is there a benefit going with one or the other? Well that question is what this article is all about. I have two identical Razer Book 13’s, one of which has the Core i5 processor and the other one sporting the Core i7, and we are basically going to put them against each other to see performance differences, and most importantly battery life. I won’t spoil the ending, but let me tell you the results are certainly worth checking out and they might actually have you second guessing your purchasing decisions.

The Specs

Before we get to the benchmarks let’s take a quick look at the spec differences between the Core i5-1135G7 and the Core i7-1165 G7. The naming scheme is ridiculous, but I had to like train myself to not make a mistake. First and foremost, they are both 4 core CPUs with 8 threads, but their base and boosts frequencies are different. The Core i5 starts at 2.4GHz and features a single core boost up to 4.2GHz, while the Core i7 starts at 2.8GHz and boost all the way up to 4.7GHz, which is a good 500MHz higher than the i5 on single core. Then there is the cache size, you are looking at 8MB on the Core i5 versus 12MB on the Core i7. The number of execution units for the integrated XE graphics are different as well, you get 80 on the Core i5 and 96 on the Core i7. The rest of the specs are pretty much the same, which includes the power operating range and the graphics frequency, which is at 1.3GHz.

Aside from that, both of these laptops are practically identical in terms of design features and even the battery capacity, except for the memory. The Core i7 model comes with 16GB versus 8GB on the Core i5 model, and storage is also the same at 256GB. If you look at the price difference the Core i7 model is $400 more than the Core i5 model, and this isn’t even the Razer Tax a lot of you mentioned. This kind of jump is something that we have seen on other Tiger Lake laptops, so yes say hello to the Intel Tax. There is also one other small difference and that is in weight. This is not a huge deal breaker, but the Core i7 model is actually 60 grams heavier than the Core i5. You might be wondering what’s causing that, it’s not like one CPU is heavier than the other one, but I think it might be because of the additional memory soldered onto the PCB or maybe a little extra cooling.

Either way, this is actually a great little laptop, and if you want to check out my review on the Book 13 you can click right here. I do want to make a slight correction from that review since some people pointed out that I didn’t get the correct brightness level or the brightness value compared to everyone else. When I ran my display analysis test I actually didn’t realize that there was a setting under the display options that changes the brightness automatically depending on lighting situations. I reran that test with that disabled and I got the expected 500 nit levels, so yes this is a very bright display and it’s beautiful. I do want to take this time to sincerely apologize for making that mistake, but I do want to thank you for bringing that up.

Power / Temps / Frequencies

Now coming back to this article, some of you might be thinking to yourselves that there are hundreds of laptops out there with Tiger Lake CPU’s operating at different power levels, why does one comparison matter? While I do agree with you on that it’s just impossible for me to go out and purchase every one of them in order to give you a complete analysis, so this is probably the best apples to apples comparison that you will be getting considering they are both rocking the same identical specs right down to the interior design. So let’s kick things off with frequencies over time, and under a full multi-core workload you can see that the Core i7 starts pretty strong at just a tad over 4GHz, but a few minutes into the test it reduces down between 3.2GHz and 3.6GHz. That is pretty much expected due to Intel’s PL1 and PL2 power limits. However, when we switch gears to the Core i5 CPU, it starts at 3.7GHz for a few seconds, which is a lot lower than the Core i7, but it actually maintains a higher average frequency throughout this 10 minute test. It isn’t much at an average of just over 75MHz, but it’s still certainly there. What that means is in quicker synthetic tests, the Core i7 CPU will definitely be faster because of it’s slightly higher and slightly longer burst speed, but in longer tests like rendering these two CPUs could be very evenly matched. The Core i5 might actually come out ahead of the i7, even in cases where there aren’t any memory or cache bottlenecks.

Let’s dive in a bit further into this. At first I thought higher temperatures might have been causing the Core i7 to settle on lower speeds, but that wasn’t the case at all. It was running above 70°C compared to the Core i5, which was averaging around 68°C to 69°C. But both of those are super low compared to the 90°C+ on other thin-and-light laptops that we have been seeing. Thermal throttling isn’t playing a factor here. Looking at overall power gives a better understanding about what’s happening, and that is Razer has capped both of these chips at a long duration power limit of 20 watts. That causes a bit of an issue for the Core i7 since it obviously needed to fluctuate its clock speeds a bit more than the Core i5 to avoid chugging down more than 20W. As a result, it’s overall average speeds end up being lower.

Intel has struggled to move their low power chips beyond a quad-core architecture, so both the Core i5 and the Core i7 have the same layout with 4 cores and 8 threads. However, the Core i7 has more cache and a larger GPU, both of which need more power. That means the more efficient CPU, which is the Core i5 processor in this case, we will hit higher average frequencies when both have identical power limits like Razer implemented on the Book 13. Some of that could have been fixed Razer had just given the Core i7 a little bit more juice to play around with, and I just don’t know why they haven’t since there is obviously thermal headroom despair. Looking back this is actually something that we have seen from Intel CPU’s, especially in the laptop market. It isn’t Razer specific either, and it would impact other laptops as well. Razer was actually the only brand who was willing to let us test these on two identical laptops. Now if you look on the desktop side, we can see something similar with the Core i7-10850K, which can manage to beat the Core i9-10900K in a lot of situations.

To hammer this home just a bit more, let’s take a look at Handbrake Transcode, which absolutely pounds the cores and local cache. Here you can see that the Core i5 is actually quite a bit faster than the Core i7 to the tune of about 100MHz, though in some cases it is above 150MHz. Meanwhile, temperatures are kept really well in check with Razer’s Vapor Chamber Cooling system. Seeing a max of just over 70°C is pretty incredible, and yes that power limit sticks to 20W so you can see how that Core i7 is just craving for a bit more juice so it can stretch its legs. Since every application needs are different, especially when it comes to all-core loads, expect some really interesting results. I also noticed that as I was testing the Book 13 with the Core i7 CPU, the fans just kept ramping up, even when I was doing lightly thread tasks compared to the Core i5 which was dead silent, so if acoustic performance is something that you value choosing the Core i5 might be a better option.

Benchmarks

Now that you are aware of how these CPUs behave, let’s take a look at some numbers. We ran our usual suite of tests, and I also made sure to run both these laptops on the highest performance mode to get the best results. Starting off with Cinebench, and I need to explain this one right away. You see every run had a huge amount of variance, which is normal for Cinebench, but the Core i7 was just really all over the place. On average, it was still slower than the Core i5. In blender things were neck and neck with very little difference between the two CPUs, but in Handbrake that 100-150MHz ends up really paying some benefits over a longer test, so much so that the Core i5 is the clear winner here. Even in Adobe Premiere Pro I was expecting the Core i7’s extra Execution Units (EUs) along with hardware encoding to favor the Core i7, but once again clock speeds are key. I should also mention that even though the Core i7 does have more EUs, unlike CUDA course they aren’t used here. Rather it’s the QuickSync stage that is used, and that is the same on both the Core i7 and the Core i5.

If we switch over to single core performance, the Core i7 takes the lead in all of our lightly threaded benchmarks, but to be honest with you it isn’t a noticeable difference. On paper it’s a few seconds faster here and there, but in reality when you are handling these machines on a day-to-day basis they both feel equally responsive. I was hoping that the extra 500MHz Turbo clock on the Core i7 would make a bit of a difference, but I was wrong, that Core i5 is still putting up a really good fight. And yes, the Core i7 is faster, but is that extra money worth it? Not the way I see it.

Gaming Performance

Gaming performance is another matter altogether. Keep in mind, both of these laptops aren’t geared to deliver high frame rates, but rather acceptable performance for casual gaming in some basic titles. Either way, I was just curious to find out if there was a difference, and you know what? There was! In 1080P you can get some playable frame rates with both these laptops, but the XE graphics engine with 96 execution units on the Core i7 CPU delivers a noticeable improvement in performance compared to the Core i5. We also can’t forget that the Core i5 has less cache and system memory to pull from, so at least in this situation the Core i7 is the clear winner right across the board.

Battery Life

The last thing that we have to look at is battery life, and it’s pretty much the same since both have the same number of cores and same operating wattage. The Core i5 does have a slight lead, but it’s not enough to make a huge difference. To sum this all up, both the Core i5 and the Core i7 have their strengths and weaknesses. The Core i5 takes the edge in multi-core performance and price, while the Core i7 runs away with gaming and it delivers really good lightly threaded performance, which is super important for a lot of general use cases. But again, that higher-end chip costs a whole lot more.

Conclusion

The main problem is that a lot of these Core i5 laptops compared with just 8GB of memory, which can’t be upgraded. While I didn’t encounter any issues when I was testing it, it’s actually a pretty big limitation, and you can’t ignore that factor in 2021, because everything just seems to be taking up a lot of memory. If you can find a Core i5-1135G7 with 16GB of RAM, that is the configuration that I would personally get because A) The performance is pretty good and B) You are probably gonna end up saving a lot of money instead of going with the Core i7. So on that note, thank you so much for reading, and I hope you were able to take away something from this article.