Longer calculation time & significant lagging/hanging in Excel 2016 compared to Excel 2013

I have a big file 65 MB in size with lots of SUMIFS, INDEX-MATCHES, VLOOKUPS etc. in multiple sheets.

The file opens up in excel 2013 (64 bit) on a 16 GB RAM PC and every change in a drop down menu gets calculated in 10-12 sec. and results are displayed just fine.

The same file when I open in excel 2016 (64 bit) on the same PC takes ages to calculate and calculation is hung at 7% and no matter what Drop down I change the file just does no re-calculate.

What the hell is going on here? Any one have any clues? 2016 should be an improvement on 2013 but surely does not work for me.

And I am unable to roll back to 2013 as I have Office 365 from my work company and the Office 365 no longer lets me go to 2013.

Any assistance is appreciated guys....

Sachin