This machine has a six-core SoC that has 2 fast cores and four slow ones. It's more or less equivalent to what you'd expect from a low-end laptop, which is consistent with the price.
In general, faster cores will dedicate more silicon to out-of-order or speculative execution, branch prediction, internal caches of various sorts, etc. The slow cores, OTOH, are most likely simpler, in-order cores with less less smart tricks, aiming to be simple and low-power. Vendors add/remove/tune all these tricks and more (memory channels, IO lines) to put processors in a given spot.
