Which method is better to use for reading Large file in C# , FileStream or Streamreader

Question

Hello All,
I am reading very large file containing 20000 rows, So for preformance view what Can I use so I not store file in memory and I read line by line content.
Currenty I am using

StreamReader MyStreamReader = new StreamReader(@"c:\Projects\Testing.txt");

string MyStringReader = MyStreamReader.ReadLine();

{

...
}
So I need your suggetion for it,
Thanks in Advance