It will be a six-core processor with support for Hyper-Threading and frequencies of 3.3-4.5 GHz. At least, according to test software. Previously, this CPU already appeared in the 3DMark database, but then the benchmark determined only its base frequency.
Compared with the current generation, then any Core i5 in most tasks will be slower, since there is no support for Hyper-Threading. But then the Core i5-10600 can be compared with the Core i7-8700 – their performance should be very similar.