TLDR somehow codeforces judge is working way slower than oj.uz

Hello codeforces! As the IOI is coming closer and closer, I started upsolving some of the IOI tasks. For many of you, i guess, it's not a secret that there is an IOI archive on codeforces.

Sadly I faced this problem (already at least twice): Same code running on oj.uz and on codeforces gets difent score. Surprisingly, smaller one belongs to cf.

As I thought, codeforces judge should be faster, no? Instead I have:

Problem IOI18_seats, TL on codeforces is 3 seconds, which should be enough for 2 seconds taking it to run on oj.uz

Another example:

Problem IOI19_rectangles, TLE'ing on codeforces as well, while passing on oj.uz .

Obviously, it's normal for unoptimal solutions not to pass, the only questions appear when same solution passes on oj.uz which is expected (at least, for me) to have slower judge?

I apologize in advance for pinging if that's not your responsibility, but PavelKunyavskiy, MikeMirzayanov, maybe it's a problem that can be fixed. Thanks!