Improvement on 3 Criteria Vlookup macro - vba

Question

I have a list with 3 variables in the sheet "Combined" in columns A; B; C.
The workbook contains 98 sheets, with those 3 variables still in A; B; C columns but in different combinations and with a fourth column which never repeats itself, as the sheets go on, which i need to bring in the "Combined" sheet, always adding another column for the next sheet I vlookup. : A B C + D(from the next sheet) + E(from the next sheet) and so on.
I have a UDF that Vlookups on 3 based on 3 criterias and a macro that cycles through the sheets and bring the values where i want them. The problem is, it's pretty slow, left it from yesterday and its on sheet 60. Any suggestions on improving it would greatly help, Thank you in advance!
Function ThreeVlookup(Table_Range As Range, Return_Col As Long, Col1_Fnd, Col2_Fnd, Col3_Fnd)
Dim rCheck As Range, bFound As Boolean, lLoop As Long
On Error Resume Next
Set rCheck = Table_Range.Columns(1).Cells(1, 1)
With WorksheetFunction
For lLoop = 1 To .CountIf(Table_Range.Columns(1), Col1_Fnd)
Set rCheck = Table_Range.Columns(1).Find(Col1_Fnd, rCheck, xlValues, xlWhole, xlNext, xlRows, False)
If UCase(rCheck(1, 2)) = UCase(Col2_Fnd) And UCase(rCheck(1, 3)) = UCase(Col3_Fnd) Then
bFound = True
Exit For
End If
Next lLoop
End With
If bFound = True Then
ThreeVlookup = rCheck(1, Return_Col)
Else
ThreeVlookup = ""
End If
End Function
Sub test()
Dim lookupVal1 As Range, lookupVal2 As Range, lookupVal3 As Range, myString As Variant, n&, u As Long
n = Sheets("Combined").[A:A].Cells.Find("*", , , , xlByRows, xlPrevious).Row
u = 4
For j = 2 To Worksheets.Count
For i = 1 To n
Set lookupVal1 = Sheets("Combined").Cells(i, 1)
Set lookupVal2 = Sheets("Combined").Cells(i, 2)
Set lookupVal3 = Sheets("Combined").Cells(i, 3)
myString = ThreeVlookup(Sheets(j).Range("A:D"), 4, lookupVal1, lookupVal2, lookupVal3)
Sheets("Combined").Cells(i, u) = myString
Next i
u = u + 1
Next j
End Sub

Answer 1

Use Arrays to speed it up, my friend! Load all your sheets (or just the current sheet in the loop) into an array in VBA's memory and do the .CountIf and .Find on arrayVar(row) instead of Table_Range.Columns(1).
You will be really surprised how much quicker it goes. Do it!
Here's a tutorial I like on arrays...
http://www.cpearson.com/excel/ArraysAndRanges.aspx
Here's a guy who speed-tested an application like yours...
https://fastexcel.wordpress.com/2011/10/26/match-vs-find-vs-variant-array-vba-performance-shootout/
The basics is like this:
Sub Play_With_Arrays()
Dim varArray() As Variant
Dim lngArray() As Long
ReDim varArray(1 To 1000)
ReDim lngArray(1 To 1000)
For A = 1 To 1000
lngArray(A) = A / 2
varArray(A) = A / 2 & " examples"
Next
searchterm = 345
For B = 1 To 1000
If lngArray(B) = searchterm Then
FoundRow = B
End If
Next
searchterm2 = "5 ex"
FoundStrRowCount = 0
For C = 1 To 1000
If InStr(1, varArray(C), searchterm2, vbBinaryCompare) Then
FoundStrRowCount = FoundStrRowCount + 1
End If
Next
MsgBox (FoundRow & " in long array and " & FoundStrRowCount & " in var array")
End Sub

Answer 2

Something like this should be much faster:
Public Function ThreeVLookup(ByVal arg_Col1LookupVal As Variant, _
ByVal arg_Col2LookupVal As Variant, _
ByVal arg_Col3LookupVal As Variant, _
ByVal arg_LookupTable As Range, _
ByVal arg_ReturnColumn As Long) _
As Variant
Dim rConstants As Range, rFormulas As Range
Dim rAdjustedTable As Range
Dim aTable As Variant
Dim i As Long
On Error Resume Next
Set rConstants = arg_LookupTable.SpecialCells(xlCellTypeConstants)
Set rFormulas = arg_LookupTable.SpecialCells(xlCellTypeFormulas)
On Error GoTo 0
Select Case (Not rConstants Is Nothing) + 2 * (Not rFormulas Is Nothing)
Case 0: ThreeVLookup = vbNullString
Exit Function
Case -1: Set rAdjustedTable = rConstants
Case -2: Set rAdjustedTable = rFormulas
Case -3: Set rAdjustedTable = Union(rConstants, rFormulas)
End Select
If WorksheetFunction.CountIfs(rAdjustedTable.Resize(, 1), arg_Col1LookupVal, rAdjustedTable.Resize(, 1).Offset(, 1), arg_Col2LookupVal, rAdjustedTable.Resize(, 1).Offset(, 2), arg_Col3LookupVal) = 0 Then
ThreeVLookup = vbNullString
Exit Function
End If
aTable = rAdjustedTable.Value
For i = LBound(aTable, 1) To UBound(aTable, 1)
If aTable(i, 1) = arg_Col1LookupVal And aTable(i, 2) = arg_Col2LookupVal And aTable(i, 3) = arg_Col3LookupVal Then
ThreeVLookup = aTable(i, arg_ReturnColumn)
Exit Function
End If
Next i
End Function
Sub tgr()
Dim wb As Workbook
Dim wsCombined As Worksheet
Dim ws As Worksheet
Dim aResults() As Variant
Dim aCombined As Variant
Dim i As Long, j As Long
Set wb = ActiveWorkbook
Set wsCombined = wb.Sheets("Combined")
aCombined = wsCombined.Range("A1").CurrentRegion.Value
ReDim aResults(1 To UBound(aCombined, 1) - LBound(aCombined, 1) + 1, 1 To wb.Sheets.Count - 1)
For i = LBound(aCombined, 1) To UBound(aCombined, 1)
j = 0
For Each ws In wb.Sheets
If ws.Name <> wsCombined.Name Then
j = j + 1
aResults(i, j) = ThreeVLookup(aCombined(i, 1), aCombined(i, 2), aCombined(i, 3), ws.Range("A:D"), 4)
End If
Next ws
Next i
wsCombined.Range("D1").Resize(UBound(aResults, 1), UBound(aResults, 2)).Value = aResults
End Sub