speed up my code?

I need speed!

Can you help speed this up?
(The files might be the problem, each file contains 35,760 lines of numbers,)
I think the problem might be the file size. If anyone knows of a different way to store the file and import it that would be worth a shot.

Sub LoadData()
Dim Theme As Theme 'This is just my background
Set Theme = New Theme
Dim Brain As Brain 'This specifies the column and a couple other variables
Set Brain = New Brain
Dim PIO As Object
Set PIO = frmGetPID.Spreadsheet1.Sheets("Skus & PID")
Dim i As Long
Dim Brain_Item As String
Dim ImportantFile as String

If Brain.optAllowErrors = False Then
    On Error GoTo ErrorHandler
End If
Application.StatusBar = "Loading Product ID Lookup... Please Wait."

ImportantFile = Brain.INI_Path & "Skus.ini"

'Open file to read
FileNum = FreeFile
Open ImportantFile For Input As FileNum

'Loop through File
Do While Not EOF(1)
Input #FileNum, Brain_Item
    i = i + 1
    PIO.Range("A" & i).Value = Brain_Item
Loop

'Close File
Close #1
i = 0
ImportantFile = Brain.INI_Path & "PID.ini"

'Open file to read
FileNum = FreeFile
Open ImportantFile For Input As FileNum

'Loop through File
Do While Not EOF(1)
Input #FileNum, Brain_Item
    i = i + 1
    PIO.Range("B" & i).Value = Brain_Item
Loop
Application.StatusBar = False
Close #1

Exit Sub
ErrorHandler:
    frmError.Show (vbModeless)
    Resume Next
End Sub