Question

I would like to know what is better to use.

IComparer class and Compare method for sort or LINQ orderby on List. Both works fine but which one is better for large lists.

Answer 1

I would choose LINQ for two reasons.

• LINQ queries are generally shorter and easier to read.
• If you really do have a large number of elements, Linq also gives you the ability to scale out to multiple CPU cores by using PLinq, which might help you out significantly.

I would expect performance to be roughly similar for a single-threaded implementation, if you consider that the lambda expression in your OrderBy clause compiles to a function — which is pretty much all you get by implementing IComparer anyway.

That being said, you might get more of a performance boost by changing your sort algorithm to be tailored to how your data is already sorted, rather than by changing your comparison method. But I’d be willing to bet my coffee this morning that OrderBy in your Linq statements uses an implementation of Quicksort, so it’s probably pretty decent in the general case already.