Crashing Spreadsheet

The spreadsheet I'm working currently crashes after about five minutes of working on it. It isn't a memory problem because its not the largest file I currently work with and  I checked task manager and it looked like I was fine on RAM and storage. It did however show that my CPU was maxed out when working with the file. I am using some fairly complex formulas such as:

={IF(SMALL(IF(Final!$H$2:$H$18497=Calc!DY$1,Final!$A$2:$A$18497),ROW(28:87))<251,SMALL(IF(Final!$H$2:$H$18497=Calc!DY$1,Final!$A$2:$A$18497),ROW(28:87)),"")}

on a large scale. Is it possible that this could be using up all my CPU processing power or is it something else? 

Side note: I have all other applications closed when I work with this spreadsheet and nothing that I know of is running in the background.

Thanks