The difference between these two Gen is very low and matter of fact. The 11th Gen Intel Core i5-11400 Processor has a higher maximum turbo frequency than the 10th Gen Intel core i5-10400. For memory, the i5-11400 is equipped with the better performing RAM when compared to the i5-10400, but both have the same 128 GB memory size. 11th Gen is good and is a power efficient processor with just a small TDP difference. Other than that, If you are looking to not blow your budget, 10th Gen is worth better.