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

[The AchieVer]

Intel's New 15W Laptop Processor for Ultraportables

Intel unveiled a new series of U-series laptop processors last year designed for ultraportables. We'll use the term “new” loosely here. These CPUs are codenamed Whiskey Lake, and they’re still 8th generation parts that are not radically different from the previous Kaby Lake Refresh chips that came before it. The main change is the move from Intel’s 14nm+ to their 14nm++ process node, which has allowed slightly higher clock speeds within the same power envelope.

The basic design of these CPUs is unchanged which is probably why they are still being called 8th-gen parts, rather than 9th-gen to fit in with Intel’s current desktop line-up. There are only three SKUs: the Core i7-8565U and Core i5-8265U that are 4 core / 8 thread CPUs, while the Core i3-8145U is a dual-core part with 4 threads. All are 15W chips although the TDP can be configured anywhere from 10W to 25W depending on what the OEM wants.

 

The focus of this review will be the Core i7-8565U, which is essentially the new flagship 15W CPU in Intel’s line-up.

This is a little confusing as previously there was a Core i7-8650U, but the 8565U is actually clocked higher, at a single core turbo clock of 4.6 GHz (up from 4.2 GHz) and an all core turbo of 4.1 GHz, up from 3.9 GHz. The base clock is a little lower though, at 1.8 GHz compared to 1.9 GHz. And these clock speed increases are even more favorable when comparing the i7-8565U to the i7-8550U which is a more like-for-like comparison going on the naming scheme; comparing those two CPUs gives at least an 11% boost clock advantage to Whiskey Lake.

It seems that a lot of OEMs weren’t super excited by Whiskey Lake because we didn’t see a lot of laptop refreshes in 2018 that decided to use these new parts. It wasn't until recently during CES 2019 that more vendors are jumping on board, and I suspect that’s due to modest clock speed increases, making it less of an urgent or necessary upgrade.

In preparation for new 2019 laptop releases we’re going to be detailing how Whiskey Lake – specifically the Core i7-8565U – performs in comparison to a range of other laptop-class processors. This should give you a good idea of how this CPU stacks up, it won’t be a perfect reflection because laptop vendors can change a number of aspects including the cooler, memory configuration and TDPs which all impact performance, but what I’ll be showing today should be very close to what you’ll see in most laptop implementations.

Crucially, we’ve tested the Core i7-8565U using the new Razer Blade Stealth which is an excellent test platform for a number of reasons.

The new Blade Stealth uses the 25W maximum TDP configuration for this CPU, so we’ll see how this chip performs in devices that choose this configuration and have larger coolers. Dell, for example, tends to use 25W for their XPS line. Then, using Intel’s Extreme Tuning Utility, we’ve also been able to set the CPU down to its regular 15W configuration, this is the most common configuration and reflects the majority of ultraportables that will use this CPU.

Having both sets of data should give a pretty comprehensive look at how this processor performs.

The Blade Stealth is also a good platform because it includes 16GB of dual-channel DDR4, again, a common configuration and dual-channel is key because the best performing laptops have dual-channel memory. On top of this, the laptop also has GeForce MX150 graphics, however for the purpose of our testing we've disabled the discrete graphics. Our full review of Razer Blade Stealth is coming up soon, where we'll test the actual performance of this laptop with its discrete GPU.

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

Benchmarks

Starting with Cinebench R15, the multi-threaded test is a relatively short benchmark but it has a decent mix of boost and steady state clock speed behavior. Despite higher boost clocks, the 8565U in its 15W configuration ends up only 3% faster than the 8550U in the multi-threaded test.

The 25W configuration gets a healthier 11% boost, which is in line with the boost clock difference. Both configs are a fair bit faster in the single-threaded test though.

To explain what’s going on here, it’s worth looking at a clock speed comparison during the Cinebench run. Both the 15W and 25W configurations start off at their maximum all core Turbo clock speed, which is 3.7 GHz for the 8550U, and 4.1 GHz for the 8565U. However when the CPU reverts to its PL1 state, so it’s no longer boosting any more, there is quite a difference in behavior.

The 25W 8550U is sitting around the 2.6 to 2.7 GHz mark, however the 25W 8565U is up at 3.1 GHz, so that’s quite a healthy gain for the 8565U and contributes to the larger gain in performance. When looking at the 15W CPUs, the 8550U sits at 2.2 to 2.3 GHz compared to 2.3 to 2.4 GHz for the 8565U. There is a gain for the 8565U, but it’s not as large as you get at 25W.

What’s apparent here is that the advantage that 14nm++ brings to Whiskey Lake isn't all that accessible with a tiny 15W power limit. You do get a decent jump in boost clock speeds, but when the CPU reverts to its long term PL1 power state, there’s not a lot to be gained from the 8565U. However at 25W, the taps are opened a bit more and Whiskey Lake can stretch its legs to provide a decent jump in performance.

 

Looking at the Cinebench R15 performance chart again, it’s also impressive to see where the 25W configuration is sitting among the pack. The 25W 8565U is almost as fast as the Core i7-7700HQ in the multi-threaded test, and it smokes it in the single-threaded test. The 7700HQ is a 45W quad-core designed for gaming laptops, so it’s great to see that performance now available in ultraportable form factors.

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

Handbrake x265 was a really interesting benchmark to run as it shows an even harsher reality for the 15W configuration of these CPUs. With this TDP limit, there was no difference in performance between the 8550U and 8565U, likely due to the use of AVX instructions that further limit what low-power CPUs can achieve.

However with the 25W configurations, the 8565U is a good 17% faster, which is slightly above the difference in long term clock speeds. We also see that while the 8565U was close to the 7700HQ in previous tests, when AVX is required, the 7700HQ and other 45W CPUs begin to pull away.

Adobe Premiere benefits strongly from GPU acceleration and the iGPU in these 15W CPUs is pretty weak. You can see that the top three CPUs that are paired with discrete-class graphics smoke the competition here. We also see the 15W 8565U fall slightly behind the 8550U, a strange result and the only benchmark where this was the case. That said, the 25W configuration is now 14% faster.

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

MATLAB is another good result for the 8565U, with an 8% gain present with the 15W configuration over the 8550U, while the 25W config jumps that up to a 14% gain. Again in this short-burst, single-core workload there’s not a lot of difference between most of Intel’s recent CPUs, and considering it also thrives on memory bandwidth where there has been virtually no improvement, we’re left with a big clumping at the top of the chart.

With 7-Zip we see small gen-on-gen improvements with Whiskey Lake again, mostly because this test is short and runs in the boost clock zone.

Adobe Photoshop shows some of the largest gains between generations with the 15W SKU delivering 13% more performance and the 25W SKU showing gains of 26%, much higher than the average.

 

It’s also worth looking at PCMark 10 where we see decent generational gains between each CPU again. The 15W SKU provides 12% more performance, which is in line with some of the single-threaded short burst workloads we’ve seen, and that’s largely what PCMark tests.

Briefly touching on GPU performance, there’s not a lot to say considering there are no changes to the GPU in Whiskey Lake compared to Kaby Lake Refresh. Big gains are expected for the next generation, but we’re not getting anything here.

Looking across our 3DMark workloads like Sky Diver, most of the gains you’re seeing are from higher CPU scores, while looking at pure GPU scores there is next to no improvement. In more GPU intensive workloads, Whiskey Lake still gets handily beaten by AMD’s Ryzen Mobile processors.

Let's now look through some overall summaries of how the Core i7-8565U performs...

On average, the 15W configuration of the 8565U is 8% faster than the 8550U, though these gains largely appear in either single-threaded workloads, short workloads, or some combination of the two. In longer workloads like encoding, you can expect less than a 5% performance improvement.

When comparing 25W configurations, the gains are more significant. Here we’re up to a 15% improvement on average with quite a healthy gain in longer workloads. This is more in line with the clock speed differences between the two processors; the 8565U is simply clocked higher so you can expect it to perform better, especially with a higher power limit.

The 25W Core i7-8565U is also now delivering performance in line with the 45W Core i7-7700HQ in some workloads; the 8565U is less than one percent behind on average. This means that in the space of roughly two years, Intel has been able to take gaming laptop level CPU performance and put that into ultraportable-type chassis. Sure, you need to use the upper-end 25W configuration to achieve this, but it’s impressive nonetheless.

 

And finally comparing the 15W 8565U to even just the Core i7-7500U from a few years ago. It’s a no-contest. With double the core and thread count, the 8565U is on average 35% faster and that margin only increases when looking strictly at multi-core workloads. If you’re coming from a dual-core ultraportable to a quad-core Whiskey Lake system, expect to see significant performance improvements across all workloads, either from the doubling of cores or from large clock speed gains.

Wrap Up

There are a couple of ways to look at what Whiskey Lake brings to the table. On one hand, there’s not a lot to be gained in its 15W configuration. We’re looking at mostly single-digit improvements and sometimes for longer workloads, no improvements compared to Kaby Lake Refresh. Intel’s 14nm node is clearly limiting and the shift to 14nm++ can only do so much.

The best you’ll get from Whiskey Lake is in its 25W configuration where performance improvements tend to match the clock speed gains more closely at around a 15% improvement. However it’s rare to find a 25W system. The 15W config is much more common, so for the majority of buyers looking at a Whiskey Lake system, there’s not a lot of incentive to upgrade from Kaby Lake Refresh or to buy a Whiskey Lake system if it costs more than a last-gen Kaby Lake-R machine.

However it’s hard not to be impressed with what Intel has achieved over the last few years without significant advances to process technology. Sure, on the desktop 14nm+++ is now a bit of a joke and performance gains – outside of increased core counts – are anywhere from unimpressive to non-existent.

But on the mobile side, within the same sorts of ultraportable laptop designs we’ve gone from two cores at modest clock speeds, to four cores at reasonably high clock speeds, on largely the same process node and architecture. Performance that used to be restricted to gaming laptops is now accessible in more portable form factors, which is very impressive.

And while Whiskey Lake isn’t a huge step over Kaby Lake Refresh, it will be a massive improvement to anyone upgrading from a 7th-gen system or earlier. Typical laptop upgrade cycles are quite long. If you’re using a four year old laptop for example, you can expect huge improvements upgrading to something 8th-gen. That said, I’d still shop around because you don’t necessarily need Whiskey Lake to access those gains, Kaby Lake-R is also fine.

There is still one lingering issue with Intel’s mobile processors, and that’s the GPU side. With basically zero improvement in this department for generations now, Intel is lagging way behind what is required for a modern ultraportable. AMD realized this as their beefy Vega GPU in their Ryzen Mobile APUs handily crush Intel’s integrated graphics. Lots of OEMs have also realized, and are starting to pair Nvidia’s MX150 discrete GPU with Intel’s 15W CPUs to get that extra GPU performance.

It does seem like Whiskey Lake is a bit of a stop gap until Intel can get their 10nm CPUs out the door at the end of 2019, which will bring a much larger and competitive Gen11 integrated GPU.

With only 5 to 15% performance gains on the CPU side, it’s all Intel could do at this point. OEMs are not exactly rushing out Whiskey Lake systems and we believe the small gains are a reflection of that.

 

 

Source

[Jogs]

The performance gain is so minute that most users will never notice.