We were pleasantly surprised recently when we looked at the Core i7-10710U. This was the first demonstration of what Intel can still do on 14nm to squeeze more performance. The 10710U packs six cores and twelve threads into a 15W package. Even though this CPU runs below 2.0 GHz in long term tests to get all those cores working within such a tight TDP, it still managed to deliver up to 30% more performance than 8th-gen CPUs.

This is down to Intel optimizing the efficiency point of this CPU. By reducing clock speeds slightly, Intel gained enough power budget to add in two extra cores, and these two cores more than offset the reduction in clock speed, giving us more performance in multi-threaded workloads. It makes the CPU design more complex and expensive and the gains are only present in workloads that use more than four cores, but there's no doubt the gains are there.

Today we're checking out another 10th-generation Intel CPU, and like the last one, this chip is much more interesting than it appears at face value. You'd think that with these 14nm+++ CPUs Intel has basically nothing left in the tank, but even with the quad-core we're reviewing today, that's surprisingly far from the truth.

The aforementioned i7-10710U is the only CPU in Intel's new 10th-gen line-up that has six cores. The rest are quad-cores, or even dual-cores if we go down to the Core i3s, Celerons and Pentiums. The Core i7-10510U, for example, is a four core eight thread CPU but it's clocked a decent amount higher than the six-core 10710U, with its 1.8 GHz base clock and 4.9 GHz maximum turbo clock. This is higher than any Whiskey Lake CPU as well, especially the popular Core i7-8565U, which is clocked up to 300 MHz lower.

Then we get to the CPU we're reviewing today, The Intel Core i5-10210U sports four cores and eight threads, but with a few reductions compared to the Core i7 models. Clock speeds are lower, at a 1.6 GHz base clock and maximum single core turbo of 4.2 GHz.

That's a little higher than the equivalent last-gen Core i5 on the maximum turbo speed, but not hugely different. Similar story with the all-core turbo, which sits with the 10210U at 3.9 GHz, up from 3.7 GHz. With both of these clocks, we aren't quite at the level of the Core i7-8565U, but generally speaking, for a 15W processor we are power limited rather than clock limited and that's something we'll explore throughout the review.

The other important factor here is the L3 cache size, which drops down from 8 MB to 6 MB as with previous Core i5 models, with unified access across the same number of cores. On a less important note, the GPU remains the same, a UHD 620 with 24 execution units. It's clocked 50 MHz lower on the Core i5 compared to past Core i7s, but what you should know is this is only a serviceable GPU that's barely changed from when Skylake U-series CPUs launched all those years ago.

As we mentioned in our previous 10th-gen Core review, Intel hasn't made it easy for the average laptop buyer to figure out which CPU they are getting and at what performance level. Comet Lake, the line-up we've just been talking about, exists alongside Ice Lake on 10nm. Ice Lake CPUs are limited to quad-core designs at lower clock speeds on the CPU, but have beefier integrated graphics with up to 64 execution units. Customers after the best CPU performance should be on the look out for Comet Lake, while those that need better GPUs might be more interested in Ice Lake.

The naming scheme is simply unfriendly though. The Comet Lake Core i5 chip we are reviewing today is the Core i5-10210U. While Ice Lake Core i5s get names like Core i5-1035G1 or Core i5-1035G7, depending on the graphics configuration. There's also the Core i5-1030G4 and G7 at 9W rather than 15W, further muddying the waters. This really needs to be simplified.

Combine this with the fact that many laptops also come with low-power discrete GPUs to beef up graphics performance. So grabbing an Ice Lake laptop might not even deliver the best GPU experience, relative to a Comet Lake product with a discrete GPU.

Moving on, you will want to know Comet Lake comes with a few additional features compared to previous-gen products, so it isn't a simple refresh with different clock speeds. We're now getting support for memory up to DDR4-2666 speeds or LPDDR4x-2933, as well as native Wi-Fi 6 support. But the bigger improvement comes in the form of something called Intel Adaptix, which we didn't cover in our Core i7-10710U review as it wasn't enabled on the laptop we tested.

Adaptix is a feature new to not just Comet Lake, but 10th-gen CPUs in general, so right now this also includes Ice Lake. It's a new version of Intel's dynamic tuning technology that takes turbo boosts a step further than we've seen previously in a mobile form factor.

Before, with Intel's 8th-gen CPUs you would get two power limits: PL1, which is the long term power limit, and PL2, the short term limit for turbo boost. When a workload gets fired up, the CPU would jump up to PL2 for a predetermined amount of time, then cut back to PL1 when that time is up. So on a 15W laptop, that would typically be a boost up to 45W for a few seconds with higher clock speeds, then a drop straight down to 15W for the rest of the workload.

Intel Adaptix changes this. Instead of dropping down to the sustained PL1 limit, Adaptix adjusts the PL1 limit dynamically over time to maximize performance based on the limits of the system. These limits are typically thermal constraints. This could see the system run at above the long term PL1 limit for a much longer time because the thermal limit of the system hasn't been reached.

In some ways, the old system was leaving a lot of potential performance on the table. If the system dropped down to PL1 well before the cooler had heated up to its sustainable limit, it could have boosted for longer to reach the limit sooner, before then dropping down. Adaptix is aimed at solving that problem and Intel says it delivers 8-12 percent more performance. However, Adaptix is optional and requires a lot of profiling on the OEM side, so it's only enabled on some systems.

Our Core i5-10210U test platform is Adaptix enabled, and it's none other than the new Asus ZenBook Pro Duo.

This is an interesting laptop to test as it comes with a second screen above the keyboard. We've been using this laptop for the last few weeks. For the stuff we normally do on a laptop like web browsing, spreadsheet editing and so on, the second screen isn't all that useful but for some people, having it there could be handy. It's a very unique design and overall the laptop is very portable, fitting into a 14-inch form factor.

The exact model we have on hand is the ZenBook Pro Duo UX481FL. It uses a 14-inch 1080p display, the Core i5-10210U processor, GeForce MX250 graphics, and 8GB of DDR4 memory. You can get up to Core i7 CPUs and 16GB of RAM in here, although it's nice to see the MX250 is retained for the Core i5 model. For the purpose of testing the i5-10210U thoroughly though, we've benchmarked with both the MX250 enabled and disabled.

Benchmarks

We're going to kick this one off with a look at Cinebench R20. First, let's quickly run through the configurations we have here. This is the standard Core i5-10210U running with Adaptix manually disabled, in a standard 15W configuration. This gives us an apples-to-apples comparison with other U-series CPUs, which are configured to 15W here as well unless otherwise specified. This is what a typical buyer can expect from a 10210U laptop where Adaptix is not used.

Then we have two 18W configurations, one with Adaptix enabled, and another without. The reason we've configured it up to 18W here, is that the ZenBook Pro Duo comes by default with a long-term PL1 limit of around 17 to 19W, hovering between that mark with Adaptix enabled out of the box. We can then manually limit the CPU to a PL1 of 18W using the Intel Extreme Tuning Utility, and that gives us a look at the performance benefit we're getting from Adaptix specifically, and whether or not it's worth finding laptops with this optional feature enabled.

The first thing to note is that this 10th-gen Comet Lake Core i5 is not far away from Intel's 8th-gen Whiskey Lake Core i7 in the i7-8565U. We're only about 4 percent behind and faster in the single-threaded test, which is impressive from a mid-range Core i5. However, comparing Core i5 to Core i7 in the 10th-generation, and the Core i5 is 23 percent slower, so those extra two cores you get with the 10710U are a significant addition for this type of workload.

We're also getting a good look at Intel's Adaptix technology. In this benchmark, having Adaptix enabled is delivering an 11% performance improvement from being able to boost that bit higher in this medium-term test.

We can see above what's happening to clock speeds with a look at Cinebench R20. Without Adaptix, the 10210U performs as we've always seen from Intel mobile CPUs. We get a short period boosting into the PL2 state, this time clocked around 3.7 to 3.9 GHz which is expected given this CPU's maximum all-core turbo frequency. Then it drops down and maintains a consistent clock during PL1, which is around 2.5 GHz configured at 18W, or 2.3 GHz at 15W.

With Adaptix enabled, the chart looks very different. We still get that boost period right at the start, but immediately after that, instead of dropping right down to PL1, clock speeds gradually fall away and only half way through the test do we see them reach the long term limit of about 18W, delivering 2.5 GHz all-core. So for more than half this test we're benefitting from clock speeds over a GHz higher in some situations, as we're running closer to the thermal limits.

There's no guarantee that this clock speed behavior will be the same for all Adaptix laptops, in fact, we can almost guarantee there there will be variations depending on the cooling capabilities. This Asus laptop seems to have strong cooling, so this is probably a best case scenario.

Looking at the older Cinebench R15, we're getting an even higher performance boost from Adaptix. This is because Cinebench R15's multi-threaded test is quicker to run, so even more of the benchmark run occurs during a boost phase. This gives the 10210U very impressive results, nearly matching the 10710U.

Something else to note, the boost in performance you get from Intel's Adaptix technology will depend on how you are using your system or how the workload is configured. If your system is idle before running a certain CPU intensive task, you'll get the biggest benefit, and might see even bigger gains than we're showing here. If you've been doing a few moderate tasks, you'll get a moderate improvement, and if you've just been smashing your CPU at 100% utilization, it's unlikely you'll see any gain. For these benchmarks we perform an average of three runs back to back, so the first run tends to produce a higher score with Adaptix enabled than the successive runs. Generally our numbers represent a 'mixed' use case where you may go from doing one thing, straight into another, with some small periods of idle in between.

In longer workloads, the benefits of Adaptix are reduced. Here we have x264 encoding, and we're only getting a 6% performance gain in pass 1, and just 2 percent in pass 2. When the CPU falls back to long term limits, there's no difference in clock speeds and thus no difference in performance between the two modes.

That said, in this benchmark it's nice to see the i5-10210U and i7-8565U providing about the same performance. The new six-core model takes things up a notch again with this 10th-gen line-up, but getting last year's Core i7 performance in this year's Core i5 is not bad at all.

Similar story in Handbrake, although this test is very limited by the 15W TDP of these CPUs. The i5-10210U is about 5% behind last year's 8565U, but also 5% faster than Intel's Core i5 from two generations ago. For further gains in Handbrake you need more cores or a higher TDP.

In 7-zip, the i5-10210U is marginally ahead of the Core i7-8565U in decompression and marginally behind in compression, so trading blows with last-gen's Core i7. Adaptix provides a small boost, 8 percent in decompression and 4 percent in compression, which again is also decent. A Core i5-10210U laptop with Adaptix enabled will easily beat Intel's last-gen offerings if configured to similar long term PL1 TDPs, not just in this test but also in general.

PCMark 10 is a collection of shorter workloads and single threaded stuff, but the 10210U does pretty well here, clocking in 6 percent faster, similar to what we saw with 7-zip, another shorter workload.

In Adobe Photoshop Iris Blur we're seeing the 10210U perform around the same level as the 8565U, in what is a shorter CPU limited benchmark. Adaptix is very impressive here, too, providing an additional 12 percent, which is one of the better results and not surprising given the test takes under 30 seconds. Once again, we're right in that ballpark estimate Intel gave about Adaptix providing 8 to 12 percent more performance.

Adobe Premiere with Lumetri effects is a more compute heavy benchmark, and one where the Core i5-10210U is slower than the Core i7-8565U by about 10 percent, which is one of the larger margins we've seen so far. Some of this will be down to CPU performance, the rest will be from the slight downclock on the GPU, given this benchmark really benefits from a faster GPU. We can see that from adding an MX250, the 10210U completes the render three times quicker, which is why those editing Premiere will want to source a laptop that has a discrete GPU.

In Adobe Photoshop Smart Sharpen, no real difference between CPUs that feature Intel's UHD 620 GPU. This is a GPU limited test, so without any improvement in GPU going from 8th-gen to 10th-gen, we're stuck here with weak performance.

Blender is another benchmark where the Core i5-10210U comes close to the Core i7-8565U, but ultimately falls just short, coming in about 3 percent slower. It is, however, much faster than Intel's Core i5-8250U from two generations ago, and Adaptix provides an additional 7 percent in this test if it's enabled.

It's no surprise to see not much of a performance gain in MATLAB, unless we're comparing this generation to several generations ago.

And finally we have a look at GPU performance again with CompuBench Optical Flow, which again shows the limitations of Intel's integrated graphics. You'd want something with an MX250 inside to get much better GPU and compute performance, or maybe a Ryzen APU will be tempting.

Performance Breakdown

Core i5-10210U vs. Core i7-8565U

As you may have noticed by our numerous mentions throughout the review, for us the most telling comparison is the one between the Core i5-10210U and the Core i7-8565U. They deliver about even performance on average, so it's somewhat safe to say that when both CPUs are configured to 15W, Intel's 10th-gen Core i5 performs like an 8th-gen Whiskey Lake Core i7.

With Intel opening a new product category for Comet Lake Core i7s, now offering six cores, it seems they have pushed what used to be Core i7 performance, down to the Core i5 tier. We love to see this sort of improvements year on year and faster CPUs hit more mid-range products. Unfortunately we haven't reviewed any Whiskey Lake Core i5, so the best Core i5 comparison we have is the Core i5-8250U from Kaby Lake-R two years ago. However, this remains a highly relevant comparison considering only a minority will be upgrading their machine after a year of use.

Core i5-10210U vs. Core i5-8250U

In this case we're seeing a 20 percent improvement on average, which is impressive after just two years. Most of this is down to clock speeds and process refinements, but again, getting Core i7 performance from a Core i5 is basically the result here. And it's possible to push those gains further if you can find a laptop that supports Adaptix technology.

Core i5-10210U: Adaptix on vs. off

We recorded a 5-6% percent performance gain from this feature on average, although this will depend on the workload. If we're comparing an Adaptix-enabled i5-10210U to any of Intel's 8th-gen U-series models, we're looking at a small but significant performance gain given this is a mainstream oriented Core i5 CPU.

Core i5-10210U vs. Core i7-10710U

Compared to the new six-core Core i7 over this quad-core Core i5. The i5 is about 17 percent slower on average, which is a similar gap to what we saw comparing Core i5 to Core i7 with Kaby Lake Refresh. Back then, the difference was due to clock speeds, now it's down to core counts, so a shift in thinking here from Intel to allow them to continue the life of 14nm.

Core i5-10210U vs. Ryzen 5 2500U

When tossing up Core i5 versus Ryzen 5, there's a big performance advantage in CPU limited tasks for Intel's 10th-generation CPU. Yes, this is the 2500U not the newer 3500U, but the 3500U is only clocked 100 MHz higher which isn't going to close the performance gap. The Ryzen 2500U does have a much faster integrated GPU.

However if you can find a Core i5-10210U paired with an MX250, generally this will be all round faster than a Ryzen 5 system, especially in workloads like Premiere which stress the CPU and GPU depending on the effects you're using. The MX250 is more than twice as fast as Intel's integrated graphics and we expect most flagship ultraportables to consider this sort of GPU even for their Core i5 offerings.

Wrap Up

This is another impressive 10th-generation U-series offering from Intel. Whiskey Lake didn't offer much of a gain over Kaby Lake Refresh because both were stuck with four core designs and there wasn't much room to go up in terms of clock speeds. But with Intel unlocking six cores with this generation, suddenly the entire stack can get shifted up, and we see the Core i5-10210U now performing like a Core i7 of old.

Intel's new Adaptix algorithm provides a decent performance boost as well, especially for shorter workloads, which if enabled, delivers double digit gains in some scenarios. The only downside to this is that Adaptix is an optional feature that needs to be implemented and optimized by laptop manufacturers, possibly on a per model basis. And it remains to be seen if it's a feature they will advertise or even list on the spec sheet.

Finally, it will be interesting to see how these CPUs end up competing with AMD's next generation of Ryzen Mobile featuring 7nm technology, and how Ice Lake can stack up there as well.

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