Testing Intel Whiskey Lake CPUs: Core i7-8565U Overview

Intel launched a new line of U-series laptop processors for ultra-portable devices last year. We will use the term "new" loosely here. These CPUs are codenamed Whiskey Lake and are still parts of the 8th generation that are not fundamentally different from the previous Kaby Lake refresh chips. The most important change is the switch from Intel 14nm + to its 14nm ++ process node, which has enabled slightly higher clock speeds with the same scope of performance.

The basic design of these CPUs is unchanged, which is why they are likely still referred to as part of the 8th generation and not as part of the 9th generation to fit into the current Intel desktop product range. There are only three SKUs: Core i7-8565U and Core i5-8265U with 4 core / 8-thread CPUs, while the Core i3-8145U is a dual-core part with 4 threads. All are 15 W chips, although the TDP can be configured between 10 W and 25 W depending on the OEM's preference.

The focus of this test will be on the Core i7-8565U, which is essentially the new flagship of the 15 W CPU in the Intel product range.

This is somewhat confusing since there was a Core i7-8650U before, but the 8565U is actually clocked higher, with a single-core turbo clock of 4.6 GHz (from 4.2 GHz) and an all-core turbo from 4.1 GHz from 3.9 GHz. However, the base clock is somewhat lower at 1.8 GHz than at 1.9 GHz. And these clock rate increases are even cheaper when you compare the i7-8565U with the i7-8550U, which is a comparable comparison of the naming scheme. Comparing these two CPUs gives Whiskey Lake a boost clock advantage of at least 11%.

It seems that many Whiskey Lake OEMs weren't particularly thrilled as we didn't see many laptop updates in 2018 that chose to use these new parts. Recently, more vendors jumped on board during CES 2019, and I suspect this is due to a modest increase in clock speed, making the upgrade less urgent or necessary.

In preparation for the new 2019 laptop versions, we'll describe in detail how Whiskey Lake – especially the Core i7-8565U – works compared to a number of other laptop-class processors. This should give you a good idea of ​​how this CPU is built. It won't be a perfect reflection as laptop vendors can change a number of aspects, including the cooler, memory configuration, and TDPs, all of which will affect performance, but what I will be today should be very close to that what you will see in most laptop implementations.

It is crucial that we tested the Core i7-8565U with the new Razer Blade Stealth, which is an excellent test platform for several reasons.

The new Blade Stealth uses the maximum TDP configuration of 25 W for this CPU. So we'll see how this chip behaves on devices that choose this configuration and have larger coolers. For example, Dell uses 25W for its XPS line. With the Intel Extreme Tuning Utility, we were also able to reset the CPU to the regular 15 W configuration. This is the most common configuration and reflects the majority of the ultraportables that use this CPU.

If you have both records, you should get a fairly comprehensive overview of this processor's performance.

The Blade Stealth is also a good platform as it contains 16 GB of dual-channel DDR4. Here too, a common configuration and two-channel is the key, since the most powerful laptops have two-channel memory. The laptop also has GeForce MX150 graphics. However, we have deactivated the discrete graphics for our tests. Our full review of Razer Blade Stealth is coming up. Here we will test the actual performance of this laptop with its discrete GPU.

A few other things to mention before the benchmark results on Whiskey Lake … The GPU and cache configuration remains unchanged compared to Kaby Lake Refresh. We are still looking at UHD 620 graphics with up to 1150 MHz in the Core i7-8565U and 8 MB L3 cache. The typical PL2 power limits also appear to be unchanged, so we're still looking at short bursts of up to 44 W in the 15 W configuration and 51 W in the 25 W configuration.


Starting with Cinebench R15, the multithread test is a relatively short benchmark, but offers a decent mix of boost and steady clock behavior. Despite higher boost cycles, the 8565U in its 15 W configuration is only 3% faster than the 8550U in the multithread test.

The 25W configuration gets a healthier 11% boost, which is the difference in the boost clock. However, both configurations are somewhat faster in the single-threaded test.

To explain what's going on here, it's worth looking at a comparison of the clock speed during the Cinebench run. Both the 15 W and 25 W configurations start with their maximum turbo clock rate for all cores, which is 3.7 GHz for the 8550U and 4.1 GHz for the 8565U. However, when the CPU returns to the PL1 state and is no longer raised, there is a significant difference in behavior.

The 25W 8550U is between 2.6 and 2.7 GHz, but the 25W 8565U is 3.1 GHz. So this is a pretty good win for the 8565U and contributes to a bigger performance gain. For the 15 W CPUs, the 8550U is 2.2 to 2.3 GHz compared to 2.3 to 2.4 GHz for the 8565U. There's a win for the 8565U, but it's not as big as 25 W.

What is obvious here is that the advantage that 14nm ++ brings to Whiskey Lake is not too easily accessible with a tiny power limit of 15W. You get a decent jump in boost clock rates, but when the CPU returns to its long-term PL1 performance state, the 8565U can't do much. At 25 W, however, the taps are opened a little further and Whiskey Lake can stretch its legs to achieve a decent leap in performance.

If you take another look at the Cinebench R15 performance table, it is also impressive to see where the 25 W configuration is in the package. The 25W 8565U is almost as fast as the Core i7-7700HQ in the multithread test and smokes in the single-thread test. The 7700HQ is a 45 W quad core designed for gaming laptops. So it's great to see that performance is now available in ultra-portable form factors.

We see a similar situation with the x264 encoding: the 25W 8565U is right up there with the 7700HQ, while the 15W configuration offers up to 8% gain over the 8550U.

The handbrake x265 was a really interesting benchmark because it shows an even tougher reality for the 15 W configuration of these CPUs. With this TDP limit, there was no performance difference between 8550U and 8565U, probably due to the use of AVX instructions that further limit the performance of low-power CPUs.

With the 25 W configurations, however, the 8565U is a good 17% faster, which is slightly more than the difference in long-term clock speeds. We also see that while the 8565U was close to the 7700HQ in previous tests, the 7700HQ and other 45W CPUs are stripping when AVX is required.

Adobe Premiere benefits greatly from GPU acceleration and the iGPU in these 15W CPUs is quite weak. You can see that the top three CPUs paired with discrete class graphics smoke the competition here. We also see that the 15W 8565U falls slightly behind the 8550U, a strange result and the only benchmark that has been the case. The 25 W configuration is now 14% faster.

Microsoft Excel is a workload that runs entirely in the PL2 boost state, so there is no performance difference between the 25W and 15W configurations. The i7-8565U has a slight advantage over the 8550U and they both sit around the same brand as the 7700HQ, another impressive achievement.

MATLAB is another good result for the 8565U, with an 8% gain in the 15 W configuration over the 8550U, while the 25 W configuration increases this gain to 14%. Even with this single-core workload with a short burst, there is no big difference between most current Intel CPUs. Given the fact that it also depends on the memory bandwidth, for which practically no improvement has been achieved, a large clumping remains with that in the table above.

With 7-Zip we again see small improvements from gene to gene with Whiskey Lake, mainly because this test is short and running in the boost clock zone.

Adobe Photoshop has some of the largest increases between generations, with the 15W SKU delivering 13% more power and the 25W SKU showing 26% gains that are well above average.

It is also worth taking a look at PCMark 10, where we see decent generation gains between the individual CPUs again. The 15W SKU offers 12% more power, which is consistent with some of the single-threaded short-burst workloads we've seen, and that's exactly what PCMark tests.

In short, there's not much to say when you consider that the Whiskey Lake GPU hasn't changed compared to Kaby Lake Refresh. Big profits are expected for the next generation, but we don't get anything here.

When you look at our 3DMark workloads like Sky Diver, most of the benefits come from higher CPU values, while there are hardly any improvements with pure GPU values. In GPU-intensive workloads, Whiskey Lake is still easily beaten by AMD's Ryzen Mobile processors.

Now let's look at some general summaries of the Core i7-8565U's performance …

On average, the 15W configuration of the 8565U is 8% faster than that of the 8550U, although these gains mostly occur with single-threaded workloads, short workloads, or a combination of both. With longer workloads like coding, you can expect a performance improvement of less than 5%.

When comparing 25 W configurations, the gains are more significant. Here we improve on average by up to 15%, whereby the workload increases significantly with longer workloads. This corresponds more to the clock speed differences between the two processors. The 8565U is simply clocked higher, so you can expect better performance, especially at a higher performance limit.

The 25W Core i7-8565U now offers performance that matches that of the 45W Core i7-7700HQ even with some workloads. The 8565U is less than 1 percent behind on average. This means that Intel was able to transfer the CPU performance of a gaming laptop to an ultra-portable case in about two years. Of course, you'll have to use the high-end 25W configuration to achieve this, but it's still impressive.

Finally, compare the 15W 8565U with the Core i7-7500U from a few years ago. It is not a competition. With twice the number of cores and threads, the 8565U is 35% faster on average, and this scope only increases if you only deal with multi-core workloads. When you switch from an ultraportable with two cores to a whiskey lake system with four cores, you can expect significant performance improvements for all workloads, either by doubling the cores or by great clock speed gains.

Wrap up

There are several ways to see what Whiskey Lake brings to the table. On the one hand, there is not much to gain in the 15 W configuration. We mainly see single digit improvements and sometimes longer workloads, no improvements compared to Kaby Lake Refresh. Intel's 14nm node is clearly limited, and switching to 14nm – ++ can only do so much.

The best you get from Whiskey Lake is the 25W configuration, where performance improvements are more in line with the clock speed gains of around 15%. However, it is rare to find a 25 W system. The 15 W configuration is much more common. Therefore, for the majority of buyers viewing a Whiskey Lake system, there is no great incentive to upgrade Kaby Lake Refresh or buy a Whiskey Lake system if it costs more than a last generation Kaby Lake- R machine.

However, it's hard not to be impressed by what Intel has accomplished in recent years without making significant advances in process technology. Sure, 14nm +++ on the desktop is now a joke and performance improvements – apart from increased core numbers – are from nondescript to nonexistent.

On the mobile side, however, within the same kind of ultra-portable laptop designs, we've evolved from two cores with modest clock speeds to four cores with relatively high clock speeds on largely the same process node and architecture. The performance that was previously limited to gaming laptops is now available in more portable form factors, which is very impressive.

And although Whiskey Lake is not a big step above Kaby Lake Refresh, it will be a massive improvement for anyone upgrading from a 7th generation or earlier system. Typical laptop upgrade cycles are quite long. For example, if you're using a four-year-old laptop, you can expect huge improvements if you upgrade to something of the 8th generation. Still, I would still shop because you don't necessarily need Whiskey Lake to access these profits. Kaby Lake-R is fine too.

There's still a problem with Intel's mobile processors, and that's the GPU side. Since this department has had practically no improvement for generations, Intel falls far short of what is required for a modern ultraportable. AMD recognized this when their beefy Vega GPU in their Ryzen Mobile APUs easily destroyed Intel's integrated graphics. Many OEMs have also recognized this and are starting to couple Nvidia's discrete MX150 GPU with Intel's 15 W CPUs to achieve this additional GPU performance.

It seems Whiskey Lake is a little gap until Intel can launch its 10nm CPUs in late 2019, which will bring a much larger and more competitive Gen11 integrated GPU.

With only 5 to 15% performance increase on the CPU side, that's all Intel could do at this point. OEMs aren't exactly poised for Whiskey Lake systems, and we believe the small profits reflect that.

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