Once more in 14nm | Intel Comet Lake-U in Review: Complicated name and not really faster

We know the situation from the previous Whiskey Lake processors: The performance of the mobile CPUs really depends of the individual TDP configuration and the cooling performance. We are, in theory, dealing with 15W CPUs here, but most current laptops allow higher TDP levels. Our pre-production unit of the Slim 15 was set to 51W for short periods (56 seconds) and 17W sustained. This means the processor can handle short peak load (which is important in everyday scenarios) very well, but we think the value for sustained workloads (PowerLimit 1) could be higher. We expect the 17W range for compact 13-inch laptops, otherwise we expect something between 20-25W.

It is therefore important how long the processor can maintain the high Turbo clocks, especially in multi-core benchmarks. Our test unit only scratches the 51W shortly before the power consumption of the i7-10510U slowly starts to drop. Depending on the starting temperature of the CPU, the results can vary quite a bit, and we actually determined results between 700 and almost 800 points in Cinebench R15 Multi. We are already familiar with this behavior from previous generations.

Note: In addition to the default settings, we also performed the tests (especially the Cinebench loop) with additional settings. We raised the PowerLimit 1 from 17 to 30 Watts, which was not too much for the cooling solution of the Schenker Slim 15. We also tried to reduce the core voltage, but we were only able to run it at -70 mV, so there was not that much optimization potential in the case of our pre-production unit.

Much more interesting than the benchmark scores are the clocks in a direct comparison with the Whiskey Lake predecessor Core i7-8565U. We fixed the power consumption of the processor manually and compared the clocks of the two chips. There can obviously be small differences in terms of efficiency for each chip, but the results are still interesting. We only see an advantage of ~5% in CB R15 Multi for the new Comet Lake-U at a fixed power consumption of 17W. This difference is obviously not really noticeable in practice.

The most interesting Comet Lake-U model is probably the new 6-core Core i7-10710U, which should be even faster in multi-core scenarios. However, we will have to wait and see how many manufacturers will actually offer it and if the implementation is a success. The power consumption is definitely in the range of regular 45W CPUs, which is just too demanding for the majority of compact laptops.

The increased requirements from Intel for the implementation of the Core i7-10710U are another problem. The mainboards and cooling units of current models are designed for quad-core chips, which is also the case for the Schenker Slim 15 we have used. According to Intel, however, the Core i7-10710U requires up to 90W in Performance mode, which would require additional voltage regulator phases and therefore new mainboards. Even the regular Comet Lake-U have higher power requirements compared to Whiskey Lake, which is already a big challenge for manufacturers.