Can someone please give me some pointers with regard to working with large data (say 1 million rows, 200 columns) in Excel 2010?

Having the data on the worksheet from cell A1 onwards, I am trying to read it in memory via an array.

QUESTION 1. What is the difference between these two methods?

Method 1:

dim myarray()
myarray = cells(1,1).currentregion.value

Method 2:

dim myarray
myarray = cells(1,1).currentregion

The second method seems to be able to read "more data" than the first, though both fail if the data is "too big", with an out of memory message.

I have also tried this:

Method 3:

dim rng as range
set rng = thisworkbook.cells(1,1).currentregion

This method seems to be able to read the large data EVERY time and I can retrieve any element like an array, ie:

dim a as integer
a = rng.cells(10000,50) would return a value

QUESTION 2. Why use arrays if Method 3 ALWAYS enables one to read large data?