Excel 64bit on Intel i7 slower than Excel 32bit (64bit Windows) on i3

[Will from London]

Hi

I have run exact copies of an Excel file (mainly normal Excel formulae, some custom formulae and a macro that loops by copy/pasting a reference number into one cell, recalculates and then copy/paste special values a single cell result, adds one to the reference number). Calculation is manual.

Anyway running it on the local C:\Temp drives (so network isn't relevant) of each of the following:
PC 1: Intel i3-2120 3.3GHz, 8.00 GB RAM, Windows 64bit (7 Enterprise Service Pack 1), Excel Professional Plus 2013 32bit) it took 7 hours and 46 minutes.
PC 2: Intel i7-6700T 2.8GHz, 8.00 GB RAM, Windows 64bit (7 Enterprise Service Pack 1), Excel Professional Plus 2013 64bit) it took 25 hours and 22 minutes.

I'm sure that the Excel file could be more efficient but can anyone help me understand why the 64bit Excel took over 3 times as long as the 32bit?

EDIT: It saves the file once at the end of the whole process and not during the 7 or 25 hours of calculations.

Any help much appreciated.

Will

 

[Sektor]

Beg your pardon, but is it OK for you that macro runs 7 hours? Does it make some database interactions?

 

[Will from London]

Valid question but the Excel file is designed to exactly replicate a financial (well, actuarial) model in piece of software called Prophet (which was Sungard). It is performing net present value projections on 45,000 life insurance policies with bespoke charging structures. Each of the 45,000 policies has 150 variables in the inputs and then the Excel file loops through each one and does monthly projections for the next 60 years.

Prophet can do the same calculations in three minutes or so but it the Excel file is useful as a double-check and as an aid to developing the Prophet model. The need to match various intermediate results makes the Excel more clunky than it needs to be. Running the Excel file overnight once a month or so isn't an issue at all. Even running it over a weekend would not be an issue.

Here I'm trying to assess whether the i7 processor and 64 bit Office is better than the i3 processor and 32 bit Office and this 25 hours vs 7 hours came up.

 

[Sektor]

Well, without code it's hard to say what is what.
Also, did you check File -> Options -> Advanced -> Enable multi-threaded calculation settings?