How do graduate admissions committees in the US perceive grading systems other than GPA? I am a senior undergraduate student in computer engineering considering applying for Ph.D in the US. In my country we use a grading system based on percentages rather than GPA and it works as follows:


85-100% ---> Distinction
75-85% ---> Very Good
65-75% ---> Good
50-65% ---> Pass


My cumulative grade will probably be about 77% which lands me in the top third of my class. My question is how will graduate admissions committees view and evaluate my academic performance given the differences in the grading systems?
A general answer, not just for countries but even for schools in the US we're not familiar with, is that we don't know how to evaluate transcripts/grades.  Different places apply different standards, both within their curriculum, and for assigning grades.  A 77% on its own could be brilliant or horrible (and we mainly just care about grades in relevant classes).  One thing we'll sometimes do is check with other members of our department who might be familiar with the country/school's grading system and standards.

In any case, the main indicator we use for how talented and well prepared the student is are the letters of recommendation.  As long as you're getting letters from some professors who are known abroad for their research and/or are familiar with the system in the US, you should get helpful letters.