Redim Preserve using Strucutres runs VERY Slow

why does this run so slow?

it takes over 10 seconds on my machine!

for a= 1 to 10000
redim preserve TEST(ubound(TEST)+1)
next




Dim TEST() As TESTstr


Public Structure TESTstr
Dim X As String
Dim X1 As String
Dim X2 As String
Dim X3 As String
Dim X4 As String
Dim X5 As String
Dim X6 As String
Dim X7 As String
Dim X8 As String
Dim X9 As String
Dim b1 As String
Dim b2 As String
Dim b3 As String
Dim b4 As String
Dim b5 As String
Dim b6 As String
Dim b7 As String
Dim b8 As String
Dim b9 As String
End Structure