Enormous Input Test C# top solution 0.14(time) gives 8.51 on my submission

I saw that C# had the best solution for the problem Enormous Input Test. I studied the basics of C# then I submitted my code. I got 8.21. Then I just exactly copied the best solution(even the comments) which had time of 0.14 and memory 31.6M(by user jcomeau_ictx) and submitted it then it showed 8.51.Why this big difference? Are the judges processors gone bad over time?