Is the LINQ version faster than the foreach one?

Whoa! That's not a fair question - it's not comparing two similar operations.
foreach is a linear operation: unless it leaves the loop prematurely for some reason, it runs the same code (the loop body) on each element of the collection one after the other.

Linq operations do not do that: in fact Linq operations are not executed until the result is needed - so just comparing a Linq method with the equivalent foreach loop is not valid as the later will always take "n" times the code duration, but the Linq method may take a trivial amount of time to set up the operation and then return immediately without executing the "loop body" code at all.

But, even if you "force" the Linq to execute to completion immediately, it is likely to be marginally slower, (or considerably slower in some cases) because of overheads it introduces "behind the scenes" - and it is very easy to write Linq code (or Linq methods) which take longer than an equivalent foreach if you do not pay attention to what you are doing...

Use what it clearest and most appropriate in the code; only worry about "which is fastest" when you have a concrete example to compare. And then watch how you time it very carefully! :laugh: