Range() VS Cells() - run times - performance

Question

I see a lot of VBA code on this site using the Range method with For loops:
Range("A" & i)
As opposed to a proper Cells command:
Cells(i,1)
I always knew the Cells way was faster, partly because Range takes longer to resolve, and partly because concatenation (&) is a relatively slow process (as opposed to any other simple arithmetic operation - AFAIK).
So, the question is, is it really faster? By how much? Sometimes, the Range format is more readable, especially for newbies. Does the speed gain justify the slight discomfort and necessary extra explanation in replies?

Answer 1

I have done some testing to see what's what.
Method
I have tested the speeds of four scenarios. Each test consisted of a For loop doing 100 000 cycles. The core of the test was using a with statement to "grab" a cell.
For i = 1 To 100000
With Cells(i, 1)
End With
Next i
The four tests were:
Cells, variable cells - With Cells(i, 1)
Cells, single cell - With Cells(1, 1)
Range, variable cells - With Range("A" & i)
Range, single cell - Range("A1")
I have used separate subs for the four test cases, and used a fifth sub to run each of them 500 times. See the code below.
For time measurement, I have used GetTickCount to get millisecond accuracy.
Results
From 500 measurements, the results were pretty consistent. (I have run it multiple times with 100 iterations, with pretty much the same results.)
Cells Cells Range Range
(variable) (single) (variable) (single)
avg 124,3 126,4 372,0 329,8
median 125 125 374 328
mode 125 125 374 328
stdev 4,1 4,7 5,7 5,4
min 109 124 358 327
max 156 141 390 344
Interpretation
The Cells method is 2.6 times faster than an equivalent Range method. If concatenation is being used, this adds another 10% execution time, which makes the difference almost 3x. This is a huge difference.
On the other hand though, we are talking about an average of 0.001 ms VS 0.004 ms per cell operation. Unless we are running a script on more than 2-3 hundred thousand cells, this is not going to make a noticeable speed difference.
Conclusion
Yep, there is a huge speed difference.
Nope, I'm not going to bother telling people to use the Cells method unless they process huge amounts of cells.
Test set-up
Win7 64 bit
8 GB RAM
Intel Core i7-3770 # 3.40 GHz
Excel 2013 32 bit
Did I miss anything? Did I cock something up? Please don't hesitate to point it out! Cheers! :)
Code
Public Declare Function GetTickCount Lib "kernel32.dll" () As Long
Sub testCells(j As Long)
Dim i As Long
Dim t1 As Long
Dim t2 As Long
t1 = GetTickCount
For i = 1 To 100000
With Cells(i, 1)
End With
Next i
t2 = GetTickCount
Sheet4.Cells(j, 1) = t2 - t1
End Sub
Sub testRange(j As Long)
Dim i As Long
Dim t1 As Long
Dim t2 As Long
t1 = GetTickCount
For i = 1 To 100000
With Range("A" & i)
End With
Next i
t2 = GetTickCount
Sheet4.Cells(j, 2) = t2 - t1
End Sub
Sub testRangeSimple(j As Long)
Dim i As Long
Dim t1 As Long
Dim t2 As Long
t1 = GetTickCount
For i = 1 To 100000
With Range("A1")
End With
Next i
t2 = GetTickCount
Sheet4.Cells(j, 3) = t2 - t1
End Sub
Sub testCellsSimple(j As Long)
Dim i As Long
Dim t1 As Long
Dim t2 As Long
t1 = GetTickCount
For i = 1 To 100000
With Cells(1, 1)
End With
Next i
t2 = GetTickCount
Sheet4.Cells(j, 4) = t2 - t1
End Sub
Sub runtests()
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
Dim j As Long
DoEvents
For j = 1 To 500
testCells j
Next j
DoEvents
For j = 1 To 500
testRange j
Next j
DoEvents
For j = 1 To 500
testRangeSimple j
Next j
DoEvents
For j = 1 To 500
testCellsSimple j
Next j
Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True
For j = 1 To 5
Beep
DoEvents
Next j
End Sub

Answer 2

I expanded upon the testing after seeing an example of .Cells(1, "A") notation which I thought might be a good balance between the readability of .Range("A1") with the speed of .Cells(1, 1)
I tested reads and writes and found for reads, .Cells(1, "A") executed in about 69% of the time .Range("A1") and .Cells(1, 1) executed in half the time of .Range("A1"). For writes there was a smaller difference (~88% and 82% respectively).
Code:
Option Explicit
Sub test()
Dim i, x, y, a, t1, t2, t3, t4
x=1000000
y=x/100
Debug.Print "---Read---" 'Cell A1 contains the number 55
t1=Timer*1000
For i = 1 to x
a = Sheet1.Range("A1")
Next
t2=Timer*1000
Debug.Print t2 - t1 & "ms"
For i = 1 to x
a = Sheet1.Cells(1, "A")
Next
t3=Timer*1000
Debug.Print t3 - t2 & "ms (" & Round(100*(t3-t2)/(t2-t1),1)&"%)"
For i = 1 to x
a = Sheet1.Cells(1, "A")
Next
t4=Timer*1000
Debug.Print t4 - t3 & "ms (" & Round(100*(t4-t3)/(t2-t1),1)&"%)"
Debug.Print "---Write---"
a=55
t1=Timer*1000
For i = 1 to y
Sheet1.Range("A1") = a
Next
t2=Timer*1000
Debug.Print t2 - t1 & "ms"
For i = 1 to y
Sheet1.Cells(1, "A") = a
Next
t3=Timer*1000
Debug.Print t3 - t2 & "ms (" & Round(100*(t3-t2)/(t2-t1),1)&"%)"
For i = 1 to y
Sheet1.Cells(1, "A") = a
Next
t4=Timer*1000
Debug.Print t4 - t3 & "ms (" & Round(100*(t4-t3)/(t2-t1),1)&"%)"
Debug.Print "----"
End Sub
^transcribed by hand, may contain typos...
Platform:
Excel 2013 32 bit
Windows 7 64 bit
16GB Ram
Xeon E5-1650 v2 #3.5GHz
(edit: changed "x" to "y" in write section of code-see disclaimer on hand-typed code!)

Answer 3

It's worth linking this stack overflow question which further explains how to increase performance:
Slow VBA macro writing in cells