Asian tech site Benchlife got its hands on the specifications of the Intel Z270 and H270 chipsets. These new chipsets will be officially introduced in early January alongside the new Kaby Lake desktop processors from Intel. Most of the currently available 100-series LGA1151 motherboards should be able to support Kaby Lake after a BIOS update, but the new chipsets offer some extra functionality.
The biggest change perhaps is that these two chipsets offer more PCI Express lanes than their Z170 and H170 predecessors. The Z270 now has a maximum of 24 PCI Express 3.0 lanes, four more than before, while the H270 has 20 lanes, also four more than the H170. Furthermore, Intel Rapid Storage Technology is update to version 15, and the new chipsets support the Intel Optane memory technology.
What sets the Z270 apart from the H270 are the same things that set the Z170 apart from the H170. The Z270 supports CPU overclocking and multi-GPU by splitting the PCI-Express 3.0 x16 PEG port from the CPU into two PCI-Express 3.0 x8 slots using 3-way lane switches. The H170 lacks CPU overclocking and multi-GPU support. You should still be able to use a pair of AMD Radeon graphics cards on the H270/H170 by running the second card on the PCI-Express x16 (electrical x4) slots some motherboards feature, since AMD drivers support this; although the performance won't be optimal, as the second card will become a strain on the DMI chipset bus.