Does filtering out errors speed up Excel?

[paulbucklandnz]

I have inherited a spreadsheet with countless formulas like this:
=IF(ISNA(MATCH(A1,MatchRange,0)),"n/a",INDEX(IndexRange,MATCH(A1,MyNamedRange,0)))

Obviously I could change these to:
=IFERROR(INDEX(IndexRange,MATCH(A1,MyNamedRange,0)),"n/a")

But I thought that instead I might just not bother checking for errors and just have:
=INDEX(IndexRange,MATCH(A1,MyNamedRange,0))
and leave the #N/A values instead of changing them to "n/a".

However, in my past experience, Excel has slowed down to a crawl if there are too many actual error results in a spreadsheet.
Would Excel run slower leaving in the real error results, so I should check them and replace with "n/a", or can I just leave the error results without a big performance hit?

Thanks!

 

[oldbrewer]

make a copy spreadsheet, do what you say, compare times, see how much time is saved.