Vlookup or index-match uses more memory?

[Dwexdwex]

I use an

{=IFERROR(vlookup(A1&"",trim(clean(Sheet2!$A$2:$B$100)),2,0),vlookup(--A1,Trim(Clean(Sheet2!$A$2:$B$100)),2,0)}

vlookup(something like that) that deters format mismatch (e.g text & numbers lookup values) and unecessary characters which kinda lags my work computer and sometimes I'm afraid that it will crash my computer and I'll lose all my files.

I am thinking of switching to index-match if it somehow uses less memory or is there any other method to this?


on a side note, how to countif the number of N/A and values in a list consisting of N/A and values?

Also, how to lookup all worksheets in a workbook? This doesn't seem to be working

{=VLOOKUP(A2,'Sheet2:Sheet10'!$C:$D,2,0)}