This seems to be pretty fast with the file created from the text in your sample file.

Option Explicit

Sub ImportTextFileToFiveColumns()
Dim fNAME As String, MyStr As String, MyARR As Variant, i As Long

'Choose a text file
    fNAME = Application.GetOpenFilename("Text Files (.txt),.txt")
    If fNAME = "False" Then Exit Sub

'Read the file into memory and split into an array
    Open fNAME For Input As #1
    Input #1, MyStr
    MyARR = Split(MyStr, " ")
    Close #1
    
'on a new sheet, parse sets of 5 values out to individual rows
    Sheets.Add
    Application.ScreenUpdating = False
    For i = 0 To UBound(MyARR) Step 5
        Range("A" & Rows.Count).End(xlUp).Offset(1).Resize(, 5).Value = Split(Join(Array(MyARR(i), MyARR(i + 1), MyARR(i + 2), MyARR(i + 3), MyARR(i + 4)), " "), " ")
    Next i
    Application.ScreenUpdating = True

End Sub