Courseload outside 6 full terms for admissions

I was wondering if as long as I get 6 terms with 5 courses done in 1st through 3rd year, does it really matter how many courses i do per semester in 4th year/spring courses? If i spend more time on ECs 4th year, and only take 3 courses per semester for example, would the fewer courses be generally looked down on in admissions compared to fuller semesters?