performance - List comprehension vs List.concat -

i have following function in (turn-based) game code, lists legal moves player in game:

let moves game =      let movestype1 game = ... //returns move list     let movestype2 game = ... //returns move list     let movestype3 game = ... //returns move list      list.concat [ (movestype1 game); (movestype2 game); (movestype3 game) ] 

now i'm wondering difference if used list comprehension , yield! following:

let moves game =      let movestype1 game = ... //returns move list     let movestype2 game = ... //returns move list     let movestype3 game = ... //returns move list      [ yield! movestype1 game       yield! movestype2 game       yield! movestype3 game ] 

i might use function many times in cases, i'm little concerned performance.

here simple test script measuring timing difference between 2 implementations:

let test1 () = list.concat [ [1..10000]; [1..10000]; [1..10000] ]  let test2 () = [ yield! [1..10000]                  yield! [1..10000]                  yield! [1..10000] ]  let runtest testimplementation =      in 1..1000         testimplementation () |> ignore #time runtest test1 //real: 00:00:02.353, cpu: 00:00:02.371, gc gen0: 143, gen1: 96, gen2: 1 #time system.gc.waitforfullgccomplete() |> ignore #time runtest test2 //real: 00:00:03.739, cpu: 00:00:03.712, gc gen0: 185, gen1: 185, gen2: 0 #time 

it appears list.concat bit better, performance things, should measure see if performance benefit matters use case.