Kaby Lake (Core i7-7500U) Review: Skylake on Steroids

Compared to the direct predecessor Core i7-6500U (2.5 GHz base, 3.1 GHz for one core, 3.0 GHz for two cores), the clocks of the Core i7-7500U (2.7 GHz base, 3.5 GHz for one core, 3.5 GHz for two cores) were increased by around 10-15 percent and therefore even surpass the Skylake top model Core i7-6600U (2.6 GHz base, 3.4 GHz for one core, 3.2 GHz for two cores).

As always, the maximum clocks are just one aspect – the processor can only maintain the specified maximum values if it does not surpass the TDP. Looking at the Core i7-7500U, this is only the case for single-threading applications, where we can see the maximum 3.5 GHz all the time. The clocks will drop from initial 3.5 GHz to 3.2-3.3 GHz after 30 seconds in multi-core scenarios. All in all, we get a respectable 15 percent advantage over a Core i7-6500U in both scenarios. Even a Core i7-6600U with an increased TDP limit of 25 Watts (ThinkPad T460s) cannot keep up with the new CPU.

Update 09/12/2016: The less powerful Core i5-7200U (2.5 GHz base clock, 3.1 GHz Turbo for one and two cores) also leaves a great impression in our benchmarks. The performance is just above the previous high-end model Core i7-6500U and only a bit slower than the i7-6600U. The maximum Turbo Boost is maintained in all single and multi-core benchmarks.

Our test sample of the i5-7200U seems to be a pretty bad example, because the chip already consumed around 16 Watts at 3.1 GHz in Cinebench R15 Multi. In theory, the CPU should have to throttle its clock by around 100 MHz, but this does not happen since Acer increased the TDP limit to 25 Watts for the test model E15 E5-575G-549D (review will follow soon). Without this, the performance would probably be 2-3 % lower.

The MSI CX72-7QL is equipped with 16 GB of the fast DDR4-2133 memory in a dual-channel configuration, which is a great way to utilize the maximum performance of the HD Graphics 620. Even though the HD Graphics 520 successor is still equipped with just 24 Execution units (EUs) and the clocks did not change, either (i7-6500U/i7-7500U: up to 1050 MHz), Intel was able to improve the performance considerably: The gaming performance is 20-30 percent higher on average, so the performance gains are even higher than the synthetic benchmarks indicated. One reason for the comparatively good results is once again the excellent Turbo Boost utilization: Depending on the game, the GPU runs at core clocks between 1000-1050 MHz.

All in all, the HD Graphics 620 is roughly on par with a dedicated Nvidia GeForce 920M or AMD Radeon R7 M440. Upcoming Kaby Lake chips with the more powerful Iris Graphics GPU (GT3e, 48 EUs, eDRAM) should even beat the GeForce 940M(X).

Intel's Kaby Lake generation admittedly looks pretty boring at first. There is no new manufacturing process, no new microarchitecture – all this reminds us a bit of the Haswell refresh back in 2014, which did not really introduce any noteworthy advantages. 

Kaby Lake on the other hand is more than just a simple rebranding of the Skylake chips. Even though the 14-nm process was basically not changed, the manufacturer was able to optimize it considerably. The results are surprisingly high clocks or a much lower consumption at the same clocks, respectively. Depending on the frequency range, we can see efficiency improvements somewhere between 15 and 25 percent; it remains to be seen whether the lower clocked Core-m/Y-series might be even better. We are also eager to see the quad-core ULV models. They are planned for 2017 and should introduce the biggest performance gains in the 15-Watt segment we have seen for years.

And last but not least, we also want to praise the reworked video decoder, which does not only support new codecs like HEVC Main10, but is also much more efficient than before. In combination with other efficiency improvements, Kaby Lake notebooks should manage even longer battery runtimes compared to their Skylake predecessors.