Temporary tables store on disk and table variables – in memory. This means that write to temp table should be significantly slower when I insert let’s say one thousand guids. However when I checked two below scripts, it turned out that the time is almost identical 877/896. Why is that?

DROP TABLE #TEST

Create Table #test
(
    Id UNIQUEIDENTIFIER 
)

DECLARE @i INT = 1;

WHILE @i < 1000
     BEGIN 
        INSERT INTO #test VALUES  (NEWID())
        SET @i = @i + 1;
    END

AND

DECLARE @table1 TABLE
(
    Id UNIQUEIDENTIFIER 
)
DECLARE @i INT = 1;

WHILE @i < 1000
     BEGIN 
        INSERT INTO #test VALUES  (NEWID())
        SET @i = @i + 1;
    END