https://arstechnica.com/gadgets/2018/06/intel-is-launching-a-28-core-enthusiast-chip-but-probably-not-at-5ghz/

Earlier this week, Intel showed off a product coming in the fourth quarter of this year: an enthusiast-oriented 28-core processor running all cores at 5GHz. This combination of clock speed and core count would put it head and shoulders above any other processor on the market, so the demonstration was more than a little surprising.

It now turns out that Intel forgot to mention an important detail: the 5GHz processors were overclocked, a lot, using chilled water coolers capable of handling thermal loads of up to 1.77kW. The real chips that ship won't be coming from the factory at 5GHz, and it's going to take a lot more than a big heatsink and a couple of fans to get them running that fast.