Way to Improve SUMPRODUCT Formula

Good morning,

I am looking for assistance to see if there is a way to improve a SUMPRODUCT formula I have. The formula works as it should, but will lock my computer up when filling the formula down to all rows. My spreadsheet this is running on usually has anywhere from 35,000 to 40,000 rows. Please let me know if there are any changes that can be made to help this formula run more efficiently.

=IF(SUMPRODUCT(($BM$3:$BM3=BM3)*($CU$3:$CU3=CU3))>1,0,1)

I am trying to enter a 1 when values in columns BM and CU for a specific row are the first occurrence of each combination.

Thanks.

Not sure how much faster it would be, but looks like you could use countifs instead of sumproduct..
And that is always preferable if it's possible..

=IF(COUNTIFS($BM$3:$BM3,BM3,$CU$3:$CU3,CU3)>1,0,1)

This does seem to be significantly quicker than the SUMPRODUCT formula. Thank you very much!

You're welcome.