
It's a dual-core, quad-threaded processor with 4MB L3 cache, a frequency of 2.4GHz and a TDP of 15W. Exact details about the ingrated graphci aren't known but it's likely the Iris 540 (GT3e) with 48 execution units and 64MB eDRAM.
The 6660U replaces the 2.2GHz Core i7 6650U and has the same $415 list price.