The Intel Core i3-7020U is a dual-core processor of the Kaby Lake architecture. It offers two CPU cores clocked at 2.3 GHz (without Turbo Boost) and integrates HyperThreading to work with up to 4 threads at once. The architectural differences are rather small compared to the Skylake generation, therefore the performance per MHz should be very similar. The SoC includes a dual channel DDR4 memory controller and Intel HD Graphics 620 graphics card (clocked at 300 - 1000 MHz). It is manufactured in an improved 14nm FinFET process at Intel. Compare to the old i3-7100U, the newer i3-7020U is clocked 100 MHz lower (CPU cores) and therefore the current entry level model for the Core i3 line. The similar Pentium Gold 4415U offers less Cache (2 versus 3 MB) and a slower GPU.
Intel basically uses the same micro architecture compared to Skylake, so the per-MHz performance does not differ. The manufacturer only reworked the Speed Shift technology for faster dynamic adjustments of voltages and clocks, and the improved 14nm process allows much higher frequencies combined with better efficiency than before.
The Intel Core i5-7500T is a power efficient desktop quad-core based on the Kaby Lake architecture. It was announced early 2017 and offers four cores and no HyperThreading (only 4 threads). The CPU clocks between 2.7 and 3.3 GHz. The integrated Intel HD Graphics 630 graphics card offers 24 EUs clocked at 350 to 1100 MHz. The TDP is specified at only 35 Watt and therefore even lower than mobile HQ quad cores (45 Watt). Thats why the CPU is also used in some laptops.
The Intel Core i7-7700HQ is a fast quad-core processor for notebooks based on the Kaby Lake H architecture (7th generation Core), which was announced in January 2017 at CES. It is the successor to the Core i7-6700HQ from the Skylake generation and is manufactured in an improved 14 nm+ process, so the clocks are 200 MHz higher at the same TDP. The architecture was not changed, only the video engine got an update (see our Kaby Lake article).
The integrated graphics card is called Intel HD Graphics 630, but the architecture does not differ from the 530 GPU from the Skylake generation and only the clocks are slightly higher.
Thanks to the 200 MHz higher clocks (5.5-7.6% depending on the Boost), the CPU performance is increased and roughly on par with the Core i7-6970HQ (2.8-3.7 GHz but with 128 MB eDRAM). The TDP can also be reduced to 35 Watts (cTDP down), but this will reduce the performance.
Due to its 45-Watt TDP, the CPU will be used in bigger notebooks with at least 15 inches most of the time.